xcode backend builds for wrong CPU architecture

[jmoguillansky-gpsw]

Describe the bug
After upgrading xcode to version 12.4, meson's xcode backend seems to try to build for all CPU architectures (e.g. arm64 and intel), instead of just the one that the user specifies. Unfortunately, when building for arm64, I get compile error (because the 3rd-party libs are compiled for intel) and the build fails.

To Reproduce
Upgrade to xcode 12.4 or newer, and try building an example project using meson, on a PC with intel CPU

Expected behavior
Meson should honor the "host" cpu param

system parameters
Native build
Mac OS Catalina
meson version 0.57.1
python version 3.9.2

** output **:

warning: ONLY_ACTIVE_ARCH=YES requested with multiple ARCHS and no run destination to provide an active architecture; building for all applicable architectures