diff --git mesa-demos-clean/meson.build mesa-demos-workdir/meson.build
index c1853f9..d30024f 100644
--- mesa-demos-clean/meson.build
+++ mesa-demos-workdir/meson.build
@@ -99,7 +99,7 @@ if not dep_glu.found() and host_machine.system() != 'darwin'
 endif
 
 dep_glx = dependency('glx', required: false, disabler : true)
-if not dep_glx.found() and host_machine.system() == 'darwin'
+if not dep_glx.found() and (host_machine.system() == 'darwin' or host_machine.system() == 'astral')
   # xquartz doesn't have a glx.pc, but it does have the header. And all the
   # symbols reside in libGL, so let's just use that.
   if cc.check_header('GL/glx.h', dependencies: dep_x11)
@@ -163,7 +163,7 @@ if cc.has_function('sincos', prefix: '#define _GNU_SOURCE\n#include <math.h>',
   add_project_arguments('-DHAVE_SINCOS', language: 'c')
 endif
 
-if ['linux', 'cygwin', 'gnu', 'freebsd', 'gnu/kfreebsd', 'haiku', 'android'].contains(host_machine.system())
+if ['linux', 'cygwin', 'gnu', 'freebsd', 'gnu/kfreebsd', 'haiku', 'android', 'astral'].contains(host_machine.system())
   add_project_arguments('-D_GNU_SOURCE', language: ['c', 'cpp'])
 elif host_machine.system() == 'windows'
   add_project_arguments(['-D_USE_MATH_DEFINES'], language: ['c', 'cpp'])
diff --git mesa-demos-clean/src/util/matrix.c mesa-demos-workdir/src/util/matrix.c
index 1d1212c..adf71dd 100644
--- mesa-demos-clean/src/util/matrix.c
+++ mesa-demos-workdir/src/util/matrix.c
@@ -9,6 +9,8 @@
 
 #include "matrix.h"
 
+#define _DEFAULT_SOURCE
+#define _GNU_SOURCE
 #include <math.h>
 #include <string.h>
 #include <stdlib.h>