Merge branch 'sg/osx-force-gcc-9'

TravisCI update. * sg/osx-force-gcc-9: ci: build Git with GCC 9 in the 'osx-gcc' build job

Junio C Hamano committed Dec 6, 2019 at 15:09 UTC ef3ce7c4b9f5ed7a13a0efcc576df855c4fd3d0f

No changes.