HPCC-15192 RelWithDebInfo CC flags should match Release

Signed-off-by: Mark Kelly <mark.kelly@lexisnexis.com>

cmake_modules/commonSetup.cmake

@@ -366,6 +366,7 @@ IF ("${COMMONSETUP_DONE}" STREQUAL "")
         endif ()
       endif ()
       SET (CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELEASE}")
+      SET (CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELEASE}")
       SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
       if (GENERATE_COVERAGE_INFO)
         message ("Build system with coverage.")