diff --git a/internal/ceres/CMakeLists.txt b/internal/ceres/CMakeLists.txt
index f077547..9475b21 100644
--- a/internal/ceres/CMakeLists.txt
+++ b/internal/ceres/CMakeLists.txt
@@ -177,21 +177,6 @@
   SOVERSION ${CERES_VERSION_MAJOR}
 )
 
-# If we are using CMake >= 2.8.11, make use of the target_compile_definitions()
-# function to append the compile definitions to the exported ceres target, thus
-# any library that finds Ceres via CMake, then adds Ceres to one of its own
-# targets will be compiled with the Ceres compile definitions defined.  This
-# is important for any defines that appear in the installed Ceres header files
-# e.g those related to shared_ptr.
-#
-# If we are using CMake < 2.8.11, then we will have added an add_definitions()
-# call in the CeresConfig.cmake file, which whilst achieving a similar effect,
-# is more of a blunt instrument, as the Ceres definitions will also be added
-# to targets in the users project that do not use Ceres.
-IF (CMAKE_VERSION VERSION_EQUAL 2.8.11 OR
-    CMAKE_VERSION VERSION_GREATER 2.8.11)
-  TARGET_COMPILE_DEFINITIONS(ceres INTERFACE ${CERES_INTERFACE_COMPILE_DEFINITIONS})
-ENDIF()
 TARGET_LINK_LIBRARIES(ceres ${CERES_LIBRARY_DEPENDENCIES})
 
 INSTALL(TARGETS ceres
diff --git a/internal/ceres/blas.cc b/internal/ceres/blas.cc
index f79b1eb..b919e13 100644
--- a/internal/ceres/blas.cc
+++ b/internal/ceres/blas.cc
@@ -29,6 +29,7 @@
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 
 #include "ceres/blas.h"
+#include "ceres/internal/port.h"
 #include "glog/logging.h"
 
 extern "C" void dsyrk_(char* uplo,
diff --git a/internal/ceres/canonical_views_clustering.cc b/internal/ceres/canonical_views_clustering.cc
index 044d438..2f032e6 100644
--- a/internal/ceres/canonical_views_clustering.cc
+++ b/internal/ceres/canonical_views_clustering.cc
@@ -29,6 +29,9 @@
 // Author: David Gallup (dgallup@google.com)
 //         Sameer Agarwal (sameeragarwal@google.com)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/canonical_views_clustering.h"
diff --git a/internal/ceres/canonical_views_clustering.h b/internal/ceres/canonical_views_clustering.h
index 06d80c8..1b4c4ee 100644
--- a/internal/ceres/canonical_views_clustering.h
+++ b/internal/ceres/canonical_views_clustering.h
@@ -41,6 +41,9 @@
 #ifndef CERES_INTERNAL_CANONICAL_VIEWS_CLUSTERING_H_
 #define CERES_INTERNAL_CANONICAL_VIEWS_CLUSTERING_H_
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include <vector>
diff --git a/internal/ceres/canonical_views_clustering_test.cc b/internal/ceres/canonical_views_clustering_test.cc
index f4f9e2d..f86084a 100644
--- a/internal/ceres/canonical_views_clustering_test.cc
+++ b/internal/ceres/canonical_views_clustering_test.cc
@@ -29,6 +29,9 @@
 // Author: Sameer Agarwal (sameeragarwal@google.com)
 //         David Gallup (dgallup@google.com)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/canonical_views_clustering.h"
diff --git a/internal/ceres/collections_port.h b/internal/ceres/collections_port.h
index e37be52..3f976b9 100644
--- a/internal/ceres/collections_port.h
+++ b/internal/ceres/collections_port.h
@@ -33,6 +33,8 @@
 #ifndef CERES_INTERNAL_COLLECTIONS_PORT_H_
 #define CERES_INTERNAL_COLLECTIONS_PORT_H_
 
+#include "ceres/internal/port.h"
+
 #if defined(CERES_NO_UNORDERED_MAP)
 #  include <map>
 #  include <set>
diff --git a/internal/ceres/cxsparse.cc b/internal/ceres/cxsparse.cc
index 7145f73..87503d0 100644
--- a/internal/ceres/cxsparse.cc
+++ b/internal/ceres/cxsparse.cc
@@ -28,6 +28,9 @@
 //
 // Author: strandmark@google.com (Petter Strandmark)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_CXSPARSE
 
 #include "ceres/cxsparse.h"
diff --git a/internal/ceres/cxsparse.h b/internal/ceres/cxsparse.h
index cd87908..1fed82f 100644
--- a/internal/ceres/cxsparse.h
+++ b/internal/ceres/cxsparse.h
@@ -31,6 +31,9 @@
 #ifndef CERES_INTERNAL_CXSPARSE_H_
 #define CERES_INTERNAL_CXSPARSE_H_
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_CXSPARSE
 
 #include <vector>
diff --git a/internal/ceres/generate_eliminator_specialization.py b/internal/ceres/generate_eliminator_specialization.py
index 37b1fd7..2ec3c5b 100644
--- a/internal/ceres/generate_eliminator_specialization.py
+++ b/internal/ceres/generate_eliminator_specialization.py
@@ -126,6 +126,9 @@
 """
 
 SPECIALIZATION_FILE = """
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generate_partitioned_matrix_view_specializations.py b/internal/ceres/generate_partitioned_matrix_view_specializations.py
index a352d29..c9bdf23 100644
--- a/internal/ceres/generate_partitioned_matrix_view_specializations.py
+++ b/internal/ceres/generate_partitioned_matrix_view_specializations.py
@@ -124,6 +124,9 @@
 """
 
 SPECIALIZATION_FILE = """
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_2_2.cc b/internal/ceres/generated/partitioned_matrix_view_2_2_2.cc
index d7bd14c..a7d802a 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_2_2.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_2_2.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_2_3.cc b/internal/ceres/generated/partitioned_matrix_view_2_2_3.cc
index 6fca7b3..89e6f77 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_2_3.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_2_3.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_2_4.cc b/internal/ceres/generated/partitioned_matrix_view_2_2_4.cc
index 73c9100..3a3e8b6 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_2_4.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_2_4.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_2_d.cc b/internal/ceres/generated/partitioned_matrix_view_2_2_d.cc
index 8315e6a..661f135 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_2_d.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_2_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_3_3.cc b/internal/ceres/generated/partitioned_matrix_view_2_3_3.cc
index dc62c20..e79e001 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_3_3.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_3_3.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_3_4.cc b/internal/ceres/generated/partitioned_matrix_view_2_3_4.cc
index de63651..2f1ae68 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_3_4.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_3_4.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_3_9.cc b/internal/ceres/generated/partitioned_matrix_view_2_3_9.cc
index f85bd62..ab40550 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_3_9.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_3_9.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_3_d.cc b/internal/ceres/generated/partitioned_matrix_view_2_3_d.cc
index 2fe07be..89ecff7 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_3_d.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_3_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_4_3.cc b/internal/ceres/generated/partitioned_matrix_view_2_4_3.cc
index ed87dcf..182707d 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_4_3.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_4_3.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_4_4.cc b/internal/ceres/generated/partitioned_matrix_view_2_4_4.cc
index 5e9a339..a2cf8f4 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_4_4.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_4_4.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_4_8.cc b/internal/ceres/generated/partitioned_matrix_view_2_4_8.cc
index aef7048..a263769 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_4_8.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_4_8.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_4_9.cc b/internal/ceres/generated/partitioned_matrix_view_2_4_9.cc
index 8fea0bd..d853860 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_4_9.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_4_9.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_4_d.cc b/internal/ceres/generated/partitioned_matrix_view_2_4_d.cc
index d9e743b..7d622fc 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_4_d.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_4_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_2_d_d.cc b/internal/ceres/generated/partitioned_matrix_view_2_d_d.cc
index 1f26134..31981ca 100644
--- a/internal/ceres/generated/partitioned_matrix_view_2_d_d.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_2_d_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_4_4_2.cc b/internal/ceres/generated/partitioned_matrix_view_4_4_2.cc
index c3c0610..d51ab5f 100644
--- a/internal/ceres/generated/partitioned_matrix_view_4_4_2.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_4_4_2.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_4_4_3.cc b/internal/ceres/generated/partitioned_matrix_view_4_4_3.cc
index 34a0944..4b17fbd 100644
--- a/internal/ceres/generated/partitioned_matrix_view_4_4_3.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_4_4_3.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_4_4_4.cc b/internal/ceres/generated/partitioned_matrix_view_4_4_4.cc
index a790d0d..7b5fe0f 100644
--- a/internal/ceres/generated/partitioned_matrix_view_4_4_4.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_4_4_4.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/partitioned_matrix_view_4_4_d.cc b/internal/ceres/generated/partitioned_matrix_view_4_4_d.cc
index 467fb0e..c31fed3 100644
--- a/internal/ceres/generated/partitioned_matrix_view_4_4_d.cc
+++ b/internal/ceres/generated/partitioned_matrix_view_4_4_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_partitioned_matrix_view_specializations.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/partitioned_matrix_view_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_2_2.cc b/internal/ceres/generated/schur_eliminator_2_2_2.cc
index 696632b..db2a4dc 100644
--- a/internal/ceres/generated/schur_eliminator_2_2_2.cc
+++ b/internal/ceres/generated/schur_eliminator_2_2_2.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_2_3.cc b/internal/ceres/generated/schur_eliminator_2_2_3.cc
index 2b92a16..f53c12a 100644
--- a/internal/ceres/generated/schur_eliminator_2_2_3.cc
+++ b/internal/ceres/generated/schur_eliminator_2_2_3.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_2_4.cc b/internal/ceres/generated/schur_eliminator_2_2_4.cc
index 5ed1625..9e29383 100644
--- a/internal/ceres/generated/schur_eliminator_2_2_4.cc
+++ b/internal/ceres/generated/schur_eliminator_2_2_4.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_2_d.cc b/internal/ceres/generated/schur_eliminator_2_2_d.cc
index 4a73090..541def6 100644
--- a/internal/ceres/generated/schur_eliminator_2_2_d.cc
+++ b/internal/ceres/generated/schur_eliminator_2_2_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_3_3.cc b/internal/ceres/generated/schur_eliminator_2_3_3.cc
index a425560..e450263 100644
--- a/internal/ceres/generated/schur_eliminator_2_3_3.cc
+++ b/internal/ceres/generated/schur_eliminator_2_3_3.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_3_4.cc b/internal/ceres/generated/schur_eliminator_2_3_4.cc
index b71a48c..0618c68 100644
--- a/internal/ceres/generated/schur_eliminator_2_3_4.cc
+++ b/internal/ceres/generated/schur_eliminator_2_3_4.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_3_9.cc b/internal/ceres/generated/schur_eliminator_2_3_9.cc
index e0c265f..c1ca665 100644
--- a/internal/ceres/generated/schur_eliminator_2_3_9.cc
+++ b/internal/ceres/generated/schur_eliminator_2_3_9.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_3_d.cc b/internal/ceres/generated/schur_eliminator_2_3_d.cc
index 31d5d6b..1b6092c 100644
--- a/internal/ceres/generated/schur_eliminator_2_3_d.cc
+++ b/internal/ceres/generated/schur_eliminator_2_3_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_4_3.cc b/internal/ceres/generated/schur_eliminator_2_4_3.cc
index cc8270d..edce8ef 100644
--- a/internal/ceres/generated/schur_eliminator_2_4_3.cc
+++ b/internal/ceres/generated/schur_eliminator_2_4_3.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_4_4.cc b/internal/ceres/generated/schur_eliminator_2_4_4.cc
index d600a8b..a6f3c52 100644
--- a/internal/ceres/generated/schur_eliminator_2_4_4.cc
+++ b/internal/ceres/generated/schur_eliminator_2_4_4.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_4_8.cc b/internal/ceres/generated/schur_eliminator_2_4_8.cc
index 81e6bd6..bf2f0ab 100644
--- a/internal/ceres/generated/schur_eliminator_2_4_8.cc
+++ b/internal/ceres/generated/schur_eliminator_2_4_8.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_4_9.cc b/internal/ceres/generated/schur_eliminator_2_4_9.cc
index 6de47d5..a63d0bb 100644
--- a/internal/ceres/generated/schur_eliminator_2_4_9.cc
+++ b/internal/ceres/generated/schur_eliminator_2_4_9.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_4_d.cc b/internal/ceres/generated/schur_eliminator_2_4_d.cc
index 716e789..b3a7fff 100644
--- a/internal/ceres/generated/schur_eliminator_2_4_d.cc
+++ b/internal/ceres/generated/schur_eliminator_2_4_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_2_d_d.cc b/internal/ceres/generated/schur_eliminator_2_d_d.cc
index 4b420c3..f4d28cd 100644
--- a/internal/ceres/generated/schur_eliminator_2_d_d.cc
+++ b/internal/ceres/generated/schur_eliminator_2_d_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_4_4_2.cc b/internal/ceres/generated/schur_eliminator_4_4_2.cc
index f944f74..d1eadc1 100644
--- a/internal/ceres/generated/schur_eliminator_4_4_2.cc
+++ b/internal/ceres/generated/schur_eliminator_4_4_2.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_4_4_3.cc b/internal/ceres/generated/schur_eliminator_4_4_3.cc
index 9787b96..c340dbf 100644
--- a/internal/ceres/generated/schur_eliminator_4_4_3.cc
+++ b/internal/ceres/generated/schur_eliminator_4_4_3.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_4_4_4.cc b/internal/ceres/generated/schur_eliminator_4_4_4.cc
index 1a25bd0..b7d58ad 100644
--- a/internal/ceres/generated/schur_eliminator_4_4_4.cc
+++ b/internal/ceres/generated/schur_eliminator_4_4_4.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/generated/schur_eliminator_4_4_d.cc b/internal/ceres/generated/schur_eliminator_4_4_d.cc
index 7ddea9f..47e0059 100644
--- a/internal/ceres/generated/schur_eliminator_4_4_d.cc
+++ b/internal/ceres/generated/schur_eliminator_4_4_d.cc
@@ -40,6 +40,9 @@
 // This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
 
 #include "ceres/schur_eliminator_impl.h"
diff --git a/internal/ceres/mutex.h b/internal/ceres/mutex.h
index 564c39f..97e2cd3 100644
--- a/internal/ceres/mutex.h
+++ b/internal/ceres/mutex.h
@@ -95,6 +95,8 @@
 #ifndef CERES_INTERNAL_MUTEX_H_
 #define CERES_INTERNAL_MUTEX_H_
 
+#include "ceres/internal/port.h"
+
 #if defined(CERES_NO_THREADS)
   typedef int MutexType;      // to keep a lock-count
 #elif defined(_WIN32) || defined(__CYGWIN32__) || defined(__CYGWIN64__)
diff --git a/internal/ceres/program_evaluator.h b/internal/ceres/program_evaluator.h
index a06dc8c..672c233 100644
--- a/internal/ceres/program_evaluator.h
+++ b/internal/ceres/program_evaluator.h
@@ -79,6 +79,9 @@
 #ifndef CERES_INTERNAL_PROGRAM_EVALUATOR_H_
 #define CERES_INTERNAL_PROGRAM_EVALUATOR_H_
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifdef CERES_USE_OPENMP
 #include <omp.h>
 #endif
diff --git a/internal/ceres/schur_eliminator_impl.h b/internal/ceres/schur_eliminator_impl.h
index c09b7fb..305d94e 100644
--- a/internal/ceres/schur_eliminator_impl.h
+++ b/internal/ceres/schur_eliminator_impl.h
@@ -45,6 +45,9 @@
 
 #define EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD 10
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifdef CERES_USE_OPENMP
 #include <omp.h>
 #endif
diff --git a/internal/ceres/single_linkage_clustering.cc b/internal/ceres/single_linkage_clustering.cc
index 54b4379..0a8b20c 100644
--- a/internal/ceres/single_linkage_clustering.cc
+++ b/internal/ceres/single_linkage_clustering.cc
@@ -28,6 +28,9 @@
 //
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/single_linkage_clustering.h"
diff --git a/internal/ceres/single_linkage_clustering.h b/internal/ceres/single_linkage_clustering.h
index 9b137cf..e6fdeab 100644
--- a/internal/ceres/single_linkage_clustering.h
+++ b/internal/ceres/single_linkage_clustering.h
@@ -31,6 +31,9 @@
 #ifndef CERES_INTERNAL_SINGLE_LINKAGE_CLUSTERING_H_
 #define CERES_INTERNAL_SINGLE_LINKAGE_CLUSTERING_H_
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/collections_port.h"
diff --git a/internal/ceres/single_linkage_clustering_test.cc b/internal/ceres/single_linkage_clustering_test.cc
index 42cbda3..1cbc5be 100644
--- a/internal/ceres/single_linkage_clustering_test.cc
+++ b/internal/ceres/single_linkage_clustering_test.cc
@@ -28,6 +28,9 @@
 //
 // Author: Sameer Agarwal (sameeragarwal@google.com)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/single_linkage_clustering.h"
diff --git a/internal/ceres/small_blas.h b/internal/ceres/small_blas.h
index e14e664..26228e4 100644
--- a/internal/ceres/small_blas.h
+++ b/internal/ceres/small_blas.h
@@ -35,6 +35,7 @@
 #ifndef CERES_INTERNAL_SMALL_BLAS_H_
 #define CERES_INTERNAL_SMALL_BLAS_H_
 
+#include "ceres/internal/port.h"
 #include "ceres/internal/eigen.h"
 #include "glog/logging.h"
 
diff --git a/internal/ceres/sparse_normal_cholesky_solver.cc b/internal/ceres/sparse_normal_cholesky_solver.cc
index 07537e3..cf5bb23 100644
--- a/internal/ceres/sparse_normal_cholesky_solver.cc
+++ b/internal/ceres/sparse_normal_cholesky_solver.cc
@@ -28,6 +28,9 @@
 //
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #if !defined(CERES_NO_SUITESPARSE) || !defined(CERES_NO_CXSPARSE)
 
 #include "ceres/sparse_normal_cholesky_solver.h"
diff --git a/internal/ceres/sparse_normal_cholesky_solver.h b/internal/ceres/sparse_normal_cholesky_solver.h
index ea91534..ed777a1 100644
--- a/internal/ceres/sparse_normal_cholesky_solver.h
+++ b/internal/ceres/sparse_normal_cholesky_solver.h
@@ -34,6 +34,9 @@
 #ifndef CERES_INTERNAL_SPARSE_NORMAL_CHOLESKY_SOLVER_H_
 #define CERES_INTERNAL_SPARSE_NORMAL_CHOLESKY_SOLVER_H_
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #if !defined(CERES_NO_SUITESPARSE) || !defined(CERES_NO_CXSPARSE)
 
 #include "ceres/cxsparse.h"
diff --git a/internal/ceres/suitesparse.cc b/internal/ceres/suitesparse.cc
index 8079bc1..1df7566 100644
--- a/internal/ceres/suitesparse.cc
+++ b/internal/ceres/suitesparse.cc
@@ -28,6 +28,9 @@
 //
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 #include "ceres/suitesparse.h"
 
diff --git a/internal/ceres/suitesparse.h b/internal/ceres/suitesparse.h
index 832f103..0a7ea97 100644
--- a/internal/ceres/suitesparse.h
+++ b/internal/ceres/suitesparse.h
@@ -33,6 +33,8 @@
 #ifndef CERES_INTERNAL_SUITESPARSE_H_
 #define CERES_INTERNAL_SUITESPARSE_H_
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
 
 #ifndef CERES_NO_SUITESPARSE
 
diff --git a/internal/ceres/visibility.cc b/internal/ceres/visibility.cc
index acfa45b..b3ee185 100644
--- a/internal/ceres/visibility.cc
+++ b/internal/ceres/visibility.cc
@@ -28,6 +28,9 @@
 //
 // Author: kushalav@google.com (Avanish Kushal)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/visibility.h"
diff --git a/internal/ceres/visibility.h b/internal/ceres/visibility.h
index 2d1e6f8..5ddd3a5 100644
--- a/internal/ceres/visibility.h
+++ b/internal/ceres/visibility.h
@@ -35,6 +35,9 @@
 #ifndef CERES_INTERNAL_VISIBILITY_H_
 #define CERES_INTERNAL_VISIBILITY_H_
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include <set>
diff --git a/internal/ceres/visibility_based_preconditioner.cc b/internal/ceres/visibility_based_preconditioner.cc
index a3bebed..695eedc 100644
--- a/internal/ceres/visibility_based_preconditioner.cc
+++ b/internal/ceres/visibility_based_preconditioner.cc
@@ -28,6 +28,9 @@
 //
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/visibility_based_preconditioner.h"
diff --git a/internal/ceres/visibility_based_preconditioner_test.cc b/internal/ceres/visibility_based_preconditioner_test.cc
index 2edbb18..c718b5e 100644
--- a/internal/ceres/visibility_based_preconditioner_test.cc
+++ b/internal/ceres/visibility_based_preconditioner_test.cc
@@ -28,6 +28,9 @@
 //
 // Author: sameeragarwal@google.com (Sameer Agarwal)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/visibility_based_preconditioner.h"
diff --git a/internal/ceres/visibility_test.cc b/internal/ceres/visibility_test.cc
index 3cfb232..0e22f88 100644
--- a/internal/ceres/visibility_test.cc
+++ b/internal/ceres/visibility_test.cc
@@ -29,6 +29,9 @@
 // Author: kushalav@google.com (Avanish Kushal)
 //         sameeragarwal@google.com (Sameer Agarwal)
 
+// This include must come before any #ifndef check on Ceres compile options.
+#include "ceres/internal/port.h"
+
 #ifndef CERES_NO_SUITESPARSE
 
 #include "ceres/visibility.h"