Don't rely on USE_GCC using implicit -isystem/usr/local/include to fix
In file included from pesign.h:30:0,
from actions.c:28:
efitypes.h:22:20: fatal error: efivar.h: No such file or directory
compilation terminated.
Reported by: http://muscles.dragonflybsd.org/bulk/latest-per-pkg/pesign/
Approved by: portmgr blanket