Disable the spanview tests on MacOS for now

And even though CI should now pass for MacOS, the llvm-cov show --debug
flag does not work when developing outside of CI, so I'm disabling it
for MacOS by default.

src/test/run-make-fulldeps/coverage-reports-base/Makefile

@@ -13,6 +13,12 @@
 BASEDIR=../coverage-reports-base
 SOURCEDIR=../coverage
 
+ifeq ($(UNAME),Darwin)
+# FIXME(richkadel): It appears that --debug is not available on MacOS even when not running
+# under CI.
+NO_LLVM_ASSERTIONS=1
+endif
+
 # The `llvm-cov show` flag `--debug`, used to generate the `counters` output files, is only enabled
 # if LLVM assertions are enabled. Some CI builds disable debug assertions.
 ifndef NO_LLVM_ASSERTIONS

src/test/run-make-fulldeps/coverage-spanview-base/Makefile

@@ -9,6 +9,10 @@
 BASEDIR=../coverage-spanview-base
 SOURCEDIR=../coverage
 
+ifeq ($(UNAME),Darwin)
+SED_HAS_ISSUES=1
+endif
+
 all: $(patsubst $(SOURCEDIR)/%.rs,%,$(wildcard $(SOURCEDIR)/*.rs))
 
 # Ensure there are no `expected` results for tests that may have been removed or renamed
@@ -29,6 +33,14 @@ endif
 			-Zdump-mir-spanview \
 			-Zdump-mir-dir="$(TMPDIR)"/mir_dump.$@
 
+ifdef SED_HAS_ISSUES
+	# FIXME(richkadel): MacOS's default sed has some significant limitations. Until I've come up
+	# with a better workaround, I'm disabling this test for MacOS.
+	#
+	# For future reference, see if `gsed` is available as an alternative.
+	which gsed || echo "no gsed"
+else
+
 	for path in "$(TMPDIR)"/mir_dump.$@/*; do \
 		echo $$path; \
 		file="$$(basename "$$path")"; \
@@ -58,3 +70,5 @@ else
 	cp "$(TMPDIR)"/mir_dump.$@/*InstrumentCoverage.0.html "$(TMPDIR)"/actual_mir_dump.$@/
 	$(DIFF) -r expected_mir_dump.$@/ "$(TMPDIR)"/actual_mir_dump.$@/
 endif
+
+endif