CMakeLists changes to make thunk buildable on CentOS 6.9

Removed Werror CFLAGS for lower version of gcc. there
will be some warning message on lower gcc version but build
is ok.

Signed-off-by: Oak Zeng <Oak.Zeng@amd.com>

Change-Id: Icf556625cb870c4ad73e1d89f3d4ade3a96e821f


[ROCm/ROCR-Runtime commit: 8176830577]

projects/rocr-runtime/CMakeLists.txt

@@ -53,7 +53,11 @@ set ( BUILD_VERSION_STRING "${BUILD_VERSION_MAJOR}.${BUILD_VERSION_MINOR}.${BUIL
 set ( CMAKE_VERBOSE_MAKEFILE on )
 
 ## Compiler flags
-set ( CMAKE_C_FLAGS "-fPIC -W -Wall -Wextra -Werror -Wno-unused-parameter -Wformat-security -Wswitch-default -Wundef -Wshadow -Wpointer-arith -Wbad-function-cast -Wcast-qual -Wlogical-op -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Wredundant-decls -Wunreachable-code -std=gnu99 -fvisibility=hidden -O2" )
+set ( CMAKE_C_FLAGS "-fPIC -W -Wall -Wextra -Wno-unused-parameter -Wformat-security -Wswitch-default -Wundef -Wshadow -Wpointer-arith -Wbad-function-cast -Wcast-qual -Wlogical-op -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Wredundant-decls -Wunreachable-code -std=gnu99 -fvisibility=hidden -O2" )
+if ( "${CMAKE_C_COMPILER_VERSION}" STRGREATER "4.8.0")
+    set ( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror" )
+endif ()
+
 
 set ( HSAKMT_LINKER_SCRIPT "${CMAKE_CURRENT_SOURCE_DIR}/src/libhsakmt.ver" )