Make it build on M1 Mac

@illwieckz In addition to these changes I also need this patch for the gtkglext repo:

From 45bceb61654ac332d1473e37e9a5a5d5485c8cce Mon Sep 17 00:00:00 2001
From: slipher <slipher@protonmail.com>
Date: Fri, 19 Aug 2022 01:04:09 -0500
Subject: [PATCH] Fix finding glib-mknenums on Mac

Assumes glib-mkenums is in the path after installing the
`glib-utils` Homebrew formula.
---
 configure.ac | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index e19683d..cfee696 100644
--- a/configure.ac
+++ b/configure.ac
@@ -232,7 +232,9 @@ PKG_CHECK_MODULES([PANGOFT2], [pangoft2], ,
                   [AS_IF([test -z "${PANGOFT2_LIBS+x}"],
                          [AC_MSG_WARN([Pango Freetype support is required to build some of the examples.])])])
 
-GLIB_MKENUMS="`$PKG_CONFIG --variable=glib_mkenums glib-2.0`"
+# brew gives bad pkgconfig info: https://github.com/Homebrew/homebrew-core/issues/108344
+# GLIB_MKENUMS="`$PKG_CONFIG --variable=glib_mkenums glib-2.0`"
+GLIB_MKENUMS="glib-mkenums"
 AC_SUBST(GLIB_MKENUMS)
 
 AX_CHECK_GL
-- 
2.32.1 (Apple Git-133)