prereq-build: fix inconsistent value of $PATH

In the recipe SetupHostCommand for checking
and creating symlinks, $PATH was only overridden
for one of several commands.

This causes the symlinks to be included
in the paths to pick a program from
when the check was repeated, because
staging_dir/host/bin was included in $PATH,
but only *sometimes*.

When the check ran again, the command succeded
with a $PATH including the symlink,
(eval "$$$$$$$$cmd")
while the path to the program was evaluated
with a $PATH NOT including the symlink,
(bin=...)
causing the symlink to be relinked incorrectly,
instead of passing as exactly the same.

Coincidentally, this was only a problem
if the symlink targeted the alternative
program with a different name.

By overriding the value of $PATH at the invocation of Make,
it will apply to the entire environment of the checks.

Signed-off-by: Michael Pratt <[email protected]>

include/prereq.mk

@@ -28,9 +28,9 @@ define Require
 
     prereq-$(1): $(if $(PREREQ_PREV),prereq-$(PREREQ_PREV)) FORCE
 		printf "Checking '$(1)'... "
-		if $(NO_TRACE_MAKE) -f $(firstword $(MAKEFILE_LIST)) check-$(1) >/dev/null 2>/dev/null; then \
+		if $(NO_TRACE_MAKE) -f $(firstword $(MAKEFILE_LIST)) check-$(1) PATH="$(ORIG_PATH)" >/dev/null 2>/dev/null; then \
 			echo 'ok.'; \
-		elif $(NO_TRACE_MAKE) -f $(firstword $(MAKEFILE_LIST)) check-$(1) >/dev/null 2>/dev/null; then \
+		elif $(NO_TRACE_MAKE) -f $(firstword $(MAKEFILE_LIST)) check-$(1) PATH="$(ORIG_PATH)" >/dev/null 2>/dev/null; then \
 			echo 'updated.'; \
 		else \
 			echo 'failed.'; \
@@ -104,8 +104,7 @@ define SetupHostCommand
 	           $(call QuoteHostCommand,$(9)) $(call QuoteHostCommand,$(10)) \
 	           $(call QuoteHostCommand,$(11)) $(call QuoteHostCommand,$(12)); do \
 		if [ -n "$$$$$$$$cmd" ]; then \
-			bin="$$$$$$$$(PATH="$(subst $(space),:,$(filter-out $(STAGING_DIR_HOST)/%,$(subst :,$(space),$(PATH))))" \
-				command -v "$$$$$$$${cmd%% *}")"; \
+			bin="$$$$$$$$(command -v "$$$$$$$${cmd%% *}")"; \
 			if [ -x "$$$$$$$$bin" ] && eval "$$$$$$$$cmd" >/dev/null 2>/dev/null; then \
 				case "$$$$$$$$(ls -dl -- $(STAGING_DIR_HOST)/bin/$(strip $(1)))" in \
 					*" -> $$$$$$$$bin"*) \