Fix CMake "LIB_SUFFIX" for non-linux installations

Change-Id: Ieb8a2825a4378b388149e7934ecc7b96ba5a29fa

internal/ceres/CMakeLists.txt

diff --git a/internal/ceres/CMakeLists.txt b/internal/ceres/CMakeLists.txt
index 703a9e7..66c258e 100644
--- a/internal/ceres/CMakeLists.txt
+++ b/internal/ceres/CMakeLists.txt
@@ -103,7 +103,8 @@
 # install native libraries to lib64 rather than lib. Most distros seem to
 # follow this convention with a couple notable exceptions (Debian-based and
 # Arch-based distros) which we try to detect here.
-IF (NOT DEFINED LIB_SUFFIX AND
+IF (${CMAKE_SYSTEM_NAME} MATCHES "Linux" AND
+    NOT DEFINED LIB_SUFFIX AND
     NOT CMAKE_CROSSCOMPILING AND
     ${CMAKE_SIZEOF_VOID_P} EQUAL "8" AND
     NOT EXISTS "/etc/debian_version" AND