[PATCH gnumach] tests/user-qemu.mk: Allow overriding command for grub-mkrescue

This allows cross built test suite to be able to be executed
in qemu by overriding the grub modules to a path containing i386-pc mods.
---
 tests/user-qemu.mk | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/user-qemu.mk b/tests/user-qemu.mk
index e497ca6d..5aeda108 100644
--- a/tests/user-qemu.mk
+++ b/tests/user-qemu.mk
@@ -174,6 +174,7 @@ tests/module-%: $(srcdir)/tests/test-%.c $(SRC_TESTLIB) $(MACH_TESTINSTALL)
 # packaging of qemu bootable image and test runner
 #
 
+GRUB_MKRESCUE ?= grub-mkrescue
 GNUMACH_ARGS = console=com0
 QEMU_OPTS = -m 2047 -nographic -no-reboot -boot d
 QEMU_GDB_PORT ?= 1234
@@ -200,7 +201,7 @@ tests/test-%.iso: tests/module-% $(GNUMACH) $(srcdir)/tests/grub.cfg.single.temp
 		>$(builddir)/tests/isofiles-$*/boot/grub/grub.cfg
 	cp $(GNUMACH) $(builddir)/tests/isofiles-$*/boot/gnumach
 	cp $< $(builddir)/tests/isofiles-$*/boot/
-	grub-mkrescue -o $@ $(builddir)/tests/isofiles-$*
+	$(GRUB_MKRESCUE) -o $@ $(builddir)/tests/isofiles-$*
 	rm -rf $(builddir)/tests/isofiles-$*
 
 tests/test-%: tests/test-%.iso $(srcdir)/tests/run-qemu.sh.template
-- 
2.49.0