use CMAKE_*_FLAGS also on unix

Author: jef-n

CMakeLists.txt

@@ -304,24 +304,17 @@ IF (PEDANTIC)
     ADD_DEFINITIONS( /wd4610 )  # user defined constructor required (sqlite3_index_info)
     ADD_DEFINITIONS( /wd4706 )  # assignment within conditional expression (pal)
   ELSE (MSVC)
-    IF (APPLE)
-      # add warnings via flags instead of definitions on Mac (otherwise -Wall can not be overridden per language)
-      SET(_warnings "-Wall -Wextra -Wno-long-long -Wformat-security -Wno-strict-aliasing")
-      SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${_warnings}")
-      SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_warnings}")
-    ELSE (APPLE)
-      ADD_DEFINITIONS( -Wall -Wextra -Wno-long-long -Wformat-security -Wno-strict-aliasing )
-    ENDIF (APPLE)
+    # add warnings via flags (not as definitions as on Mac -Wall can not be overridden per language )
+    SET(_warnings "-Wall -Wextra -Wno-long-long -Wformat-security -Wno-strict-aliasing")
+    SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${_warnings}")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_warnings}")
+
     # Qt produces lots of warnings with strict aliasing (as of Qt 4.4.0 & GCC 4.3)
     # There are redundant declarations in Qt and GDAL
     # ADD_DEFINITIONS( -fstrict-aliasing -Wstrict-aliasing=1 -Wredundant-decls )
 
     IF ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-      IF (APPLE)
-        SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-return-type-c-linkage")
-      ELSE (APPLE)
-        ADD_DEFINITIONS(-Wno-return-type-c-linkage) # used in plugins and providers
-      ENDIF (APPLE)
+      SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-return-type-c-linkage")
     ENDIF ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
   ENDIF (MSVC)