[make][buildall] add ability to filter buildall by architecture

Clean up make targets list-arch and list-toolchain to be much faster and
work without needing to invoke the archtecture's arch rules.mk. This
should make it work on machines that do not have that particular
toolchain in the path.

This is setting up for using it in the github action script.

engine.mk

@@ -183,11 +183,25 @@ include platform/$(PLATFORM)/rules.mk
 ifndef ARCH
 $(error couldn't find arch or platform doesn't define arch)
 endif
+
+# list the architecture specified in the project/target/platform rules.mk and early terminate.
+ifeq ($(MAKECMDGOALS), list-arch)
+$(info ARCH = $(ARCH))
+.PHONY: list-arch
+list-arch:
+else
+
 include arch/$(ARCH)/rules.mk
 ifndef TOOLCHAIN_PREFIX
 $(error TOOLCHAIN_PREFIX not set in the arch rules.mk)
 endif
 
+ifeq ($(MAKECMDGOALS), list-toolchain)
+$(info TOOLCHAIN_PREFIX = $(TOOLCHAIN_PREFIX))
+.PHONY: list-toolchain
+list-toolchain:
+else
+
 # default to no ccache
 CCACHE ?=
 CC ?= $(CCACHE) $(TOOLCHAIN_PREFIX)gcc
@@ -354,12 +368,6 @@ clean: $(EXTRA_CLEANDEPS)
 install: all
 	scp $(OUTBIN) 192.168.0.4:/tftpboot
 
-list-arch:
-	@echo ARCH = ${ARCH}
-
-list-toolchain:
-	@echo TOOLCHAIN_PREFIX = ${TOOLCHAIN_PREFIX}
-
 tags: $(BUILDDIR)/srcfiles.txt $(BUILDDIR)/include_paths.txt
 	$(info generating tags)
 	@ctags -L $<
@@ -382,6 +390,10 @@ ifeq ($(filter $(MAKECMDGOALS), clean), )
 -include $(DEPS)
 endif
 
+endif # ifeq ($(filter $(MAKECMDGOALS), list-toolchain))
+
+endif # ifeq ($(filter $(MAKECMDGOALS), list-arch))
+
 endif # do-nothing = 1
 
 endif # make spotless