Merge branch 'es/squelch-openssl-warnings-on-macosx' into maint

An earlier workaround to squelch unhelpful deprecation warnings from the complier on Mac OSX unnecessarily set minimum required version of the OS, which the user might want to raise (or lower) for other reasons. * es/squelch-openssl-warnings-on-macosx: git-compat-util: do not step on MAC_OS_X_VERSION_MIN_REQUIRED