work around homebrew python linking issues (#1267)

* debug python brew issues

* dbg2

* dbg3

* dbg4

* insulate workflow from homebrew location.

.github/workflows/macos.yml

@@ -73,6 +73,12 @@ jobs:
         # https://github.com/actions/runner-images/issues/6507
         # https://github.com/actions/runner-images/issues/2322
         # brew update # skip update for now to avoid link issues AND many slow dependency upGRADES.
+        brew list -1 | grep python
+        ls -l $(brew --prefix)/bin | grep -i python
+        # workaround for https://github.com/actions/setup-python/issues/577
+        brew list -1 | grep python | while read formula; do brew unlink $formula; brew link --overwrite $formula; done
+        brew list -1 | grep python
+        ls -l $(brew --prefix)/bin | grep -i python
         brew install ninja
         brew install docbook docbook-xsl fop gnu-sed
         # brew install is taking forever on macos-11, skip jing-trang and all it's dependencies.