Fix compiler flags on Linux

config/compilerFlags.cmake

@@ -1,20 +1,14 @@
 if ( MINGW OR UNIX ) # MINGW, Linux, APPLE, CYGWIN
     if (${CMAKE_CXX_COMPILER_ID} STREQUAL GNU)
-        set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -Wall
-                                               -Wcast-align
-                                               -Wpointer-arith
-                                               -Wformat-security
-                                               -Wmissing-format-attribute
-                                               -Woverloaded-virtual
-                                               -W
-            )
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wcast-align -Wpointer-arith -Wformat-security -Wmissing-format-attribute -Woverloaded-virtual -W")
     endif()
 
     if ( CYGWIN OR (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 5.0))
-        set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -std=gnu++98 ) # to support snprintf
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++98") # to support snprintf
     else()
-        set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -std=c++98 )
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++98")
     endif()
+
 endif ()
 
 # http://stackoverflow.com/questions/10113017/setting-the-msvc-runtime-in-cmake