Collections port fix for MSVC 2008

Apparently, TR1 symbols are defined in different namespace
comparing to MSVC 2010, which lead to compilation error when
using MSVC 2008.

Change-Id: I4fa3ceae4b4e2c6e7a46b1fb5b498640e7b18b74

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7518676..df8d1a7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -530,9 +530,23 @@
   # Use the std namespace for the hash<> and related templates. This may vary by
   # system.
   IF (MSVC)
-    # This is known to work with Visual Studio 2010 Express.
-    ADD_DEFINITIONS("\"-DCERES_HASH_NAMESPACE_START=namespace std {\"")
-    ADD_DEFINITIONS("\"-DCERES_HASH_NAMESPACE_END=}\"")
+    IF (MSVC90)
+      # Special case for Visual Studio 2008.
+      # Newer versions have got tr1 symbols in another namespace,
+      # and this is being handled in Else branch of this condition.
+      # Probably Visual studio 2003 and 2005 also shall be handled here,
+      # but don't have by hand to verify and most likely they're not
+      # used by Ceres users anyway.
+      ADD_DEFINITIONS("\"-DCERES_HASH_NAMESPACE_START=namespace std { namespace tr1 {\"")
+      ADD_DEFINITIONS("\"-DCERES_HASH_NAMESPACE_END=}}\"")
+    ELSE (MSVC90)
+      # This is known to work with Visual Studio 2010 Express.
+      # Further, for as long Visual Studio 2012 didn't move tr1 to
+      # just another namespace, the same define will work for it as well.
+      # Hopefully all further versions will also keep working with this define.
+      ADD_DEFINITIONS("\"-DCERES_HASH_NAMESPACE_START=namespace std {\"")
+      ADD_DEFINITIONS("\"-DCERES_HASH_NAMESPACE_END=}\"")
+    ENDIF(MSVC90)
   ELSE (MSVC)
     # This is known to work with recent versions of Linux and Mac OS X.
     ADD_DEFINITIONS("\"-DCERES_HASH_NAMESPACE_START=namespace std { namespace tr1 {\"")