diff -urpN Ardour-6.6.0.orig/libs/pbd/pbd/g_atomic_compat.h Ardour-6.6.0/libs/pbd/pbd/g_atomic_compat.h
--- Ardour-6.6.0.orig/libs/pbd/pbd/g_atomic_compat.h	2021-04-22 02:42:57.647664443 -0700
+++ Ardour-6.6.0/libs/pbd/pbd/g_atomic_compat.h	2021-04-22 02:43:39.760450842 -0700
@@ -30,7 +30,7 @@
  * Older versions of glib and older compilers still expect a volatile qualifier and print
  * "cast from type 'volatile long int*' to type 'long int*' casts away qualifiers [-Wcast-qual]"
  */
-#if defined __GNUC__ && __GNUC__ > 10
+#if defined HAVE_GLIB_2_68 && (defined(__cplusplus) && __cplusplus >= 201103L)
 #  define GATOMIC_QUAL
 #else
 #  define GATOMIC_QUAL volatile
diff -urpN Ardour-6.6.0.orig/wscript Ardour-6.6.0/wscript
--- Ardour-6.6.0.orig/wscript	2021-04-22 02:39:51.447189735 -0700
+++ Ardour-6.6.0/wscript	2021-04-22 02:43:39.760450842 -0700
@@ -1148,6 +1148,7 @@ def configure(conf):
         conf.env.append_value('LDFLAGS', '-L/usr/X11R6/lib')
 
     autowaf.check_pkg(conf, 'glib-2.0', uselib_store='GLIB', atleast_version='2.28', mandatory=True)
+    autowaf.check_pkg(conf, 'glib-2.0', uselib_store='GLIB_2_68', atleast_version='2.68', mandatory=False)
     autowaf.check_pkg(conf, 'gthread-2.0', uselib_store='GTHREAD', atleast_version='2.2', mandatory=True)
     autowaf.check_pkg(conf, 'glibmm-2.4', uselib_store='GLIBMM', atleast_version='2.32.0', mandatory=True)
     autowaf.check_pkg(conf, 'sndfile', uselib_store='SNDFILE', atleast_version='1.0.18', mandatory=True)