modules: FindSDL2.cmake cleanup.

modules/FindSDL2.cmake

@@ -35,11 +35,11 @@
 # In Emscripten SDL is linked automatically, thus no need to find the library.
 # Also the includes are in SDL subdirectory, not SDL2.
 if(CORRADE_TARGET_EMSCRIPTEN)
-    set(PATH_SUFFIXES SDL)
+    set(_SDL2_PATH_SUFFIXES SDL)
 else()
     find_library(SDL2_LIBRARY SDL2)
     set(SDL2_LIBRARY_NEEDED SDL2_LIBRARY)
-    set(PATH_SUFFIXES SDL2)
+    set(_SDL2_PATH_SUFFIXES SDL2)
 endif()
 
 # Include dir
@@ -52,11 +52,9 @@ find_path(SDL2_INCLUDE_DIR
     # this issue), but rather SDL2.framework/Headers/SDL.h, CMake might find
     # SDL.framework/Headers/SDL.h if SDL1 is installed, which is wrong.
     NAMES SDL_scancode.h
-    PATH_SUFFIXES ${PATH_SUFFIXES}
-)
+    PATH_SUFFIXES ${_SDL2_PATH_SUFFIXES})
 
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args("SDL2" DEFAULT_MSG
     ${SDL2_LIBRARY_NEEDED}
-    SDL2_INCLUDE_DIR
-)
+    SDL2_INCLUDE_DIR)