package/libgtk4: fix execinfo compile error

../testsuite/reftests/gtk-reftest.c:28:10: fatal error: execinfo.h: No such file or directory

We don't need the test suite, so disable it.

Signed-off-by: Thomas Devoogdt <thomas@devoogdt.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/libgtk4/libgtk4.mk

@@ -26,6 +26,7 @@ LIBGTK4_DEPENDENCIES = \
 
 LIBGTK4_CONF_OPTS = \
 	-Dbuild-tests=false \
+	-Dbuild-testsuite=false \
 	-Dmedia-ffmpeg=disabled \
 	-Dprint-cpdb=disabled \
 	-Dvulkan=disabled \