glib2: sync with default host prefix change

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

libs/glib2/Makefile

@@ -59,7 +59,7 @@ CONFIGURE_ARGS += \
 CONFIGURE_VARS += \
 	glib_cv_stack_grows=no \
 	glib_cv_uscore=no \
-	ac_cv_path_GLIB_GENMARSHAL=$(STAGING_DIR_HOST)/bin/glib-genmarshal \
+	ac_cv_path_GLIB_GENMARSHAL=$(STAGING_DIR)/host/bin/glib-genmarshal \
 	ac_cv_func_mmap_fixed_mapped=yes \
 	ac_cv_func_posix_getpwuid_r=yes \
 	ac_cv_func_posix_getgrgid_r=yes