Fix make test failing when test/sql/ does not exist

HISTORY.asc

@@ -1,5 +1,11 @@
 STABLE
 ------
+== Fix `make test` failing when `test/sql/` doesn't exist
+`installcheck` needs `test/sql/` to exist, but the rule that creates it was
+spelled `test/sql` (no trailing slash), which Make treats as a different
+target. A project without that directory got `No rule to make target
+'test/sql/'`; it now gets created like `test/expected/` and `results/`.
+
 == Add `make post-tag-version-bump` and `releasing-with-pgxntool.md`
 New target `post-tag-version-bump` sets each extension's `default_version`
 to a placeholder (`stable` by default) after a release, so later `make`

base.mk

@@ -658,7 +658,7 @@ print-pgtle: pgtle
 		cat "$$f";)
 
 # These targets ensure all the relevant directories exist
-$(TESTDIR)/sql $(TESTDIR)/expected/ $(TESTOUT)/results/:
+$(TESTDIR)/sql/ $(TESTDIR)/expected/ $(TESTOUT)/results/:
 	@mkdir -p $@
 # pg_regress aborts with "could not open file" if an expected output file is
 # missing, so create empty placeholders for any test that lacks one.