t/Makefile: check helper scripts for non-portable shell commands too

Currently only the "t[0-9][0-9][0-9][0-9]-*.sh" scripts are tested for
shell incompatibilities using the check-non-portable-shell.pl script. This
makes it easy to miss non-POSIX constructs added to one of the t/*lib*.sh
helper scripts, as they aren't automatically detected.

Fix that by adding a THELPERS variable containing all shell scripts that
aren't tests and add these to the "test-lint-shell-syntax" target too.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/Makefile

@@ -29,6 +29,7 @@ TEST_RESULTS_DIRECTORY_SQ = $(subst ','\'',$(TEST_RESULTS_DIRECTORY))
 T = $(sort $(wildcard t[0-9][0-9][0-9][0-9]-*.sh))
 TSVN = $(sort $(wildcard t91[0-9][0-9]-*.sh))
 TGITWEB = $(sort $(wildcard t95[0-9][0-9]-*.sh))
+THELPERS = $(sort $(filter-out $(T),$(wildcard *.sh)))
 
 all: $(DEFAULT_TEST_TARGET)
 
@@ -65,7 +66,7 @@ test-lint-executable:
 		echo >&2 "non-executable tests:" $$bad; exit 1; }
 
 test-lint-shell-syntax:
-	@'$(PERL_PATH_SQ)' check-non-portable-shell.pl $(T)
+	@'$(PERL_PATH_SQ)' check-non-portable-shell.pl $(T) $(THELPERS)
 
 aggregate-results-and-cleanup: $(T)
 	$(MAKE) aggregate-results