allow make {dist, }clean work w/out configure

There's no reason to require configure to run before running a clean
target, so check MAKECMDGOALS before.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

Makefile

@@ -14,9 +14,11 @@ config-host.mak: $(SRC_PATH)/configure
 	@sed -n "/.*Configured with/s/[^:]*: //p" $@ | sh
 else
 config-host.mak:
+ifneq ($(filter-out %clean,$(MAKECMDGOALS)),$(if $(MAKECMDGOALS),,fail))
 	@echo "Please call configure before running make!"
 	@exit 1
 endif
+endif
 
 GENERATED_HEADERS = config-host.h trace.h qemu-options.def
 ifeq ($(TRACE_BACKEND),dtrace)
@@ -403,7 +405,9 @@ qemu-doc.dvi qemu-doc.html qemu-doc.info qemu-doc.pdf: \
 
 # Add a dependency on the generated files, so that they are always
 # rebuilt before other object files
+ifneq ($(filter-out %clean,$(MAKECMDGOALS)),$(if $(MAKECMDGOALS),,fail))
 Makefile: $(GENERATED_HEADERS)
+endif
 
 # Include automatically generated dependency files
 # Dependencies in Makefile.objs files come from our recursive subdir rules