Mtime of source codes are sometimes newer than build time (clock skew?)

Environments macOS
1

This clock skew causes make install failed with Permission denied.
It should not be happen when mtime of source codes are sane.

before_script.1:

$ date
Mon Apr 29 03:18:32 GMT 2019

before_script.32:

++date
Mon Apr 29 02:55:14 GMT 2019