Fixes for makefiles, GLFW 3.1 library for Linux

src/makefile

@@ -155,8 +155,7 @@ ifeq ($(PLATFORM),PLATFORM_DESKTOP)
 		rm -f *.o libraylib.a
     else
     ifeq ($(PLATFORM_OS),LINUX)
-		find . -type f -executable -delete
-		rm -f *.o libraylib.a
+		find -type f -executable | xargs file -i | grep -E 'x-object|x-archive|x-sharedlib|x-executable' | rev | cut -d ':' -f 2- | rev | xargs rm -f
     else
 		del *.o libraylib.a
     endif