Improved how RUBYSDLFFI_PATH and SDL_PATHS are processed.

lib/ruby-sdl-ffi/sdl.rb

@@ -35,21 +35,17 @@ module SDL
   extend NiceFFI::Library
 
   unless defined? SDL::LOAD_PATHS
-    # Check if the application has defined SDL_PATHS with some
-    # paths to check first for SDL libraries.
+    SDL::LOAD_PATHS = NiceFFI::PathSet::DEFAULT.dup
 
     rubysdlffi_path = ENV["RUBYSDLFFI_PATH"]
     if rubysdlffi_path and not rubysdlffi_path.empty?
-      rubysdlffi_path = rubysdlffi_path.split( File::PATH_SEPARATOR ).compact
+      paths = rubysdlffi_path.split( File::PATH_SEPARATOR ).compact
+      SDL::LOAD_PATHS.prepend!(paths)
     end
 
-    SDL::LOAD_PATHS = if rubysdlffi_path
-                        NiceFFI::PathSet::DEFAULT.prepend( rubysdlffi_path )
-                      elsif defined? ::SDL_PATHS
-                        NiceFFI::PathSet::DEFAULT.prepend( ::SDL_PATHS )
-                      else
-                        NiceFFI::PathSet::DEFAULT
-                      end
+    if defined? ::SDL_PATHS
+      SDL::LOAD_PATHS.prepend!(::SDL_PATHS)
+    end
   end
 
   load_library "SDL", SDL::LOAD_PATHS