testsuite: Make sure we prefix the ghcconfig with a hash

Ideally, ghc should just be able to produce this data outright, without having to resort to a separate tool. This seems highly
questionable.  It would be much better if ghc should emitted
this information in a structured way.

Author: angerman

testsuite/.gitignore

@@ -60,6 +60,10 @@ tmp.d
 *.so
 *bindisttest_install___dir_bin_ghc.mk
 *bindisttest_install___dir_bin_ghc.exe.mk
+mk/*_ghcconfig*_bin_ghc*.mk
+mk/*_ghcconfig*_bin_ghc*.exe.mk
+mk/*_ghcconfig*_test___spaces_ghc*.mk
+mk/*_ghcconfig*_test___spaces_ghc*.exe.mk
 mk/ghcconfig*_bin_ghc*.mk
 mk/ghcconfig*_bin_ghc*.exe.mk
 mk/ghcconfig*_test___spaces_ghc*.mk

testsuite/mk/boilerplate.mk

@@ -260,7 +260,18 @@ $(TOP)/ghc-config/ghc-config : $(TOP)/ghc-config/ghc-config.hs
 empty=
 space=$(empty) $(empty)
 ifeq "$(ghc_config_mk)" ""
-ghc_config_mk = $(TOP)/mk/ghcconfig$(subst $(space),_,$(subst :,_,$(subst /,_,$(subst \,_,$(TEST_HC))))).mk
+sanitized_hc := $(subst $(space),_,$(subst :,_,$(subst /,_,$(subst \,_,$(TEST_HC)))))
+test_hc_hash := $(shell \
+  if command -v openssl >/dev/null 2>&1; then \
+    openssl dgst -sha256 $(TEST_HC) | awk '{print substr($$2, 1, 8)}'; \
+  elif command -v sha256sum >/dev/null 2>&1; then \
+    sha256sum $(TEST_HC) | awk '{print substr($$1, 1, 8)}'; \
+  elif command -v shasum >/dev/null 2>&1; then \
+    shasum -a 256 $(TEST_HC) | awk '{print substr($$1, 1, 8)}'; \
+  else \
+    echo "no_hash"; \
+  fi)
+ghc_config_mk = $(TOP)/mk/$(test_hc_hash)_ghcconfig$(sanitized_hc).mk
 
 $(ghc_config_mk) : $(TOP)/ghc-config/ghc-config
 	$(TOP)/ghc-config/ghc-config "$(TEST_HC)" >"$@"; if [ "$$?" != "0" ]; then $(RM) "$@"; exit 1; fi