Invalid developer path error when building on macOS

[stephane-caron]

Encountering the following error on an x86_64 Intel MacBook Pro:

ERROR: /private/var/tmp/_bazel_user/9346498e49901e13c4d5dccd1a466e2c/external/mpack/BUILD.bazel:7:11: Compiling mpack.c failed: (Exit 1): cc_wrapper.sh failed: error executing command (from target @mpack//:mpack) external/local_config_cc/cc_wrapper.sh -U_FORTIFY_SOURCE -fstack-protector -Wall -Wthread-safety -Wself-assign -Wunused-but-set-parameter -Wno-free-nonheap-object -fcolor-diagnostics ... (remaining 25 arguments skipped)

Followed by:

xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

[stephane-caron]

The solution proposed in this SO answer is to install the Command Line Tools package. It fixes this error, but causes another one down the line in this project because of the way Bazel detects the CPU architecture on macOS. To jump directly to the long-term solution:

• Install Xcode from the Mac App Store.