Enable Windows host compilation of gflags am: 791196a1e8 am: 1e32a9e8c7 am: 073396cf0a am: c7e4441964

Original change: https://android-review.googlesource.com/c/platform/external/gflags/+/2411455

Change-Id: Ibbf78b40a1a1016770d6ccc090baabf9d6c30ccb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>