macos: Use newer MACOSX_DEPLOYMENT_TARGET
macos: Use newer MACOSX_DEPLOYMENT_TARGET

10.6 seems to still be supported on Mojave, but not 10.4
anymore.

mirror/tinycc,mirror/tinycc,mingodad/tinycc,mirror/tinycc,mingodad/tinycc,mirror/tinycc,mingodad/tinycc,mingodad/tinycc