win: Decide how to include system dirs at toolchain time instead of globally.
Before this patch, we used the global is_clang setting to decide if
we include system libraries via /I or -imsvc in the clang toolchains.
Now, always use -imsvc in the clang toolchains.
The motivation is that we (maybe) want to build libyuv with a clang
toolchain even when is_clang is globally set to false.
BUG=692600
Review-Url: https://codereview.chromium.org/2728233002
Cr-Original-Commit-Position: refs/heads/master@{#454704}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: cbdbc2fd19dcde3cf06296bb9bad8f41978214b5
2 files changed
