Actually build libc++ and libc++abi with -std=c++20

build/config/compiler/BUILD.gn adds the flag to cflags_cc, so this
config here must do that too. Else the -std=c++20 will show up
on the commandline _before_ the -std=c++17 added by
build/config/compiler:compiler, rendering it ineffective.

Bug: 1298070
Change-Id: I145b04aeef1003620594a0be8f74bb7731797069
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3469402
Commit-Queue: Nico Weber <thakis@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Arthur Eubanks <aeubanks@google.com>
Commit-Queue: Arthur Eubanks <aeubanks@google.com>
Cr-Commit-Position: refs/heads/main@{#972250}
NOKEYCHECK=True
GitOrigin-RevId: d95d20a3f7cc630e324e706c0a2bd405792283c4
1 file changed