Fix close source build for tools library,

Change-Id: Id0265b186ac2fbc5385ff70e3d34947055788c21


[ROCm/ROCR-Runtime commit: a2ebd9a825]

projects/rocr-runtime/runtime/hsa-runtime-tools/CMakeLists.txt

@@ -73,7 +73,7 @@ endif()
 ## ------------------------- Linux Compiler and Linker options -------------------------
 set ( CMAKE_CXX_FLAGS "-std=c++11 ")
 
-set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror -fexceptions -fno-rtti -fvisibility=hidden -Wno-error=sign-compare -Wno-error=enum-compare -Wno-sign-compare -Wno-write-strings -Wno-deprecated-declarations -Wno-conversion-null -fno-math-errno -fno-threadsafe-statics -fmerge-all-constants -fms-extensions -Wno-error=comment -Wno-comment -Wno-error=pointer-arith -Wno-pointer-arith -fPIC" )
+set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror=return-type -Werror -fexceptions -fno-rtti -fvisibility=hidden -Wno-error=sign-compare -Wno-error=enum-compare -Wno-sign-compare -Wno-write-strings -Wno-deprecated-declarations -Wno-conversion-null -fno-math-errno -fno-threadsafe-statics -fmerge-all-constants -fms-extensions -Wno-error=comment -Wno-comment -Wno-error=pointer-arith -Wno-pointer-arith -fPIC" )
 
 if (IS64BIT)
     set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -m64  -msse -msse2" )