Avoid importing nacl config for non-NaCl toolchains.

This should help keep the NaCl configuration more separate from the rest of the
build. A comment is added to prevent regressions.

Review-Url: https://codereview.chromium.org/2845943005
Cr-Original-Commit-Position: refs/heads/master@{#468037}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: c4d0415066d9a0f98eb98179f49679906da55c87
1 file changed