Silence the OpenGL deprecation warnings on macOS 10.14

setup.py

@@ -236,6 +236,9 @@ def kitty_env():
     cflags.extend(pkg_config('libpng', '--cflags-only-I'))
     if is_macos:
         font_libs = ['-framework', 'CoreText', '-framework', 'CoreGraphics']
+        # Apple deprecated OpenGL in Mojave (10.14) silence the endless
+        # warnings about it
+        cppflags.append('-DGL_SILENCE_DEPRECATION')
     else:
         cflags.extend(pkg_config('fontconfig', '--cflags-only-I'))
         font_libs = pkg_config('fontconfig', '--libs')