fix toplevel arch/distro loops

There was a somewhat subtle Makefile->main.mk rename leftover
lurking in "everything" target: the default Makefile got used,
not the supposed main.mk -- which resulted in an attempt to
get way too much job done (the number of builds per target
became $ARCH squared, not just $ARCH).

Huge thanks to led@ for being an inspiring pedantic!

Makefile

@@ -31,6 +31,8 @@ export NUM_TARGETS := $(words $(MAKECMDGOALS))
 		echo "** goal: $@ [$$n/$(NUM_TARGETS)]"; \
 	fi; \
 	for ARCH in $(ARCHES); do \
+		if [ "$$ARCH" != "$(firstword $(ARCHES))" ]; then echo; fi; \
+		echo "** ARCH: $$ARCH"; \
 		$(MAKE) -f main.mk ARCH=$$ARCH $@; \
 	done; \
 	if [ "$$n" -lt "$(NUM_TARGETS)" ]; then echo; fi

main.mk

@@ -61,11 +61,8 @@ everything:
 	@n=1; sum=$(words $(DISTROS)); \
 	for distro in $(DISTROS); do \
 		echo "** building $$distro [$$n/$$sum]:"; \
-		$(MAKE) --no-print-directory \
-			COUNT=$$n/$$sum \
-			BUILDDIR=$(BUILDDIR) \
-			$$distro; \
-		echo; \
+		$(MAKE) -f main.mk --no-print-directory $$distro; \
+		[ "$$n" -lt "$$sum" ] && echo; \
 		n=$$(($$n+1)); \
 	done