Fix build issues related to Solaris and older GCC

Fixed two build issues:
 - JsonCPP currently doesn’t compile for Solaris due to platform
differences with ‘isfinite’ function.  Fixed by adding proper include
and define for Solaris.
 - JsonCPP currently doesn’t compile for GCC version 4.1.2 and earlier
due to use of ‘-Werror=*’ compile flag, which was introduced in a later
version.  Fixed by adding version check to only add this flag on
supported versions of GCC.

Author: dominicpezzuto

src/lib_json/CMakeLists.txt

@@ -7,7 +7,14 @@ ELSE(JSONCPP_LIB_BUILD_SHARED)
 ENDIF(JSONCPP_LIB_BUILD_SHARED)
 
 if( CMAKE_COMPILER_IS_GNUCXX )
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror=strict-aliasing")
+  #Get compiler version.
+  execute_process( COMMAND ${CMAKE_CXX_COMPILER} -dumpversion
+                   OUTPUT_VARIABLE GNUCXX_VERSION )
+
+  #-Werror=* was introduced -after- GCC 4.1.2
+  if( GNUCXX_VERSION VERSION_GREATER 4.1.2 )
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror=strict-aliasing")
+  endif()
 endif( CMAKE_COMPILER_IS_GNUCXX )
 
 SET( JSONCPP_INCLUDE_DIR ../../include )