Fuchsia: Proper Fuchsia-on-macOS cross build support
Fuchsia: Proper Fuchsia-on-macOS cross build support

https://chromium-review.googlesource.com/c/+/1503688 brings an updated
Fuchsia SDK into Crashpad. Now, a specific SDK for macOS build hosts is
available. Previously, macOS build hosts “borrowed” the Linux build host
SDK. The Fuchsia sysroot build configuration in mini_chromium needs to
be updated for this change.

Change-Id: I7b815b71d3b575c61a224f4aef82434e08fd2add
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/mini_chromium/+/1506239
Reviewed-by: Scott Graham <e134406e1863f3b48b0795831afac5c0595efb36@chromium.org>

chromium/mini_chromium,chromium/mini_chromium,chromium/mini_chromium