Two computers of mine fail to compile gcc-7.3.1-r5 with -march=skylake.

Processors affected:

• Intel(R) Xeon(R) CPU E3-1535M v5 @ 2.90GHz
• Intel(R) Xeon(R) CPU E3-1240 v5 @ 3.50GHz

epro subarch is  intel64-skylake

make.conf has CFLAGS manually set to:

CFLAGS="-march=skylake -O2 -pipe"

I am not sure if this is a bug as Gentoo Safe CFLAGS says march should possibly better set to "native".

Previously building gcc-7.3.1-r3 succeded with the above settings.