Respect user-provided CMAKE_C_FLAGS (#35)

Author: realnc

CMakeLists.txt

@@ -85,7 +85,7 @@ if ( CMAKE_COMPILER_IS_GNUCC )
           "${CMAKE_SHARED_LINKER_FLAGS} -Wl,--no-undefined" )
   endif ( NOT APPLE )
   set ( GNUCC_WARNING_FLAGS "-Wall")
-  set ( CMAKE_C_FLAGS "-pedantic" )
+  set ( CMAKE_C_FLAGS "-pedantic ${CMAKE_C_FLAGS}" )
   set ( CMAKE_C_FLAGS_DEBUG "-g -DDEBUG -fsanitize=undefined ${GNUCC_WARNING_FLAGS} ${CMAKE_C_FLAGS_DEBUG}" )
   set ( CMAKE_C_FLAGS_RELEASE "-O2 -DNDEBUG ${GNUCC_WARNING_FLAGS} ${CMAKE_C_FLAGS_RELEASE}" )
   set ( CMAKE_C_FLAGS_RELWITHDEBINFO "-O2 -g -DNDEBUG ${GNUCC_WARNING_FLAGS} ${CMAKE_C_FLAGS_RELWITHDEBINFO}" )