Removed predefined SDK path. Found that it's generally not good idea to force it. Also -Wno-unused-but-set-parameter only set for gcc 4.6 or newer

CMakeLists.txt

@@ -4,9 +4,6 @@ if (APPLE)
     set(APP_BUNDLE_NAME "${CMAKE_PROJECT_NAME}.app")
 
     set(APP_BUNDLE_DIR "${OpenMW_BINARY_DIR}/${APP_BUNDLE_NAME}")
-
-    # using 10.6 sdk
-    set(CMAKE_OSX_SYSROOT "/Developer/SDKs/MacOSX10.6.sdk")
 endif (APPLE)
 
 # Macros
@@ -287,7 +284,13 @@ endif (APPLE)
 
 # Compiler settings
 if (CMAKE_COMPILER_IS_GNUCC)
-    add_definitions (-Wall -Wextra -Wno-unused-parameter -Wno-unused-but-set-parameter -Wno-reorder)
+    add_definitions (-Wall -Wextra -Wno-unused-parameter -Wno-reorder)
+
+    execute_process(COMMAND ${CMAKE_C_COMPILER} -dumpversion
+                OUTPUT_VARIABLE GCC_VERSION)
+    if ("${GCC_VERSION}" VERSION_GREATER 4.6 OR "${GCC_VERSION}" VERSION_EQUAL 4.6)
+        add_definitions (-Wno-unused-but-set-parameter)
+    endif("${GCC_VERSION}" VERSION_GREATER 4.6 OR "${GCC_VERSION}" VERSION_EQUAL 4.6)
 endif (CMAKE_COMPILER_IS_GNUCC)
 
 if(DPKG_PROGRAM)