Always set --no-canonical-prefixes if we can
-no-canonical-prefixes should be enough in all cases except very
old compilers. For those, we keep using -fno-canonical-system-headers
Closes #7316.
PiperOrigin-RevId: 234574545
diff --git a/tools/cpp/unix_cc_configure.bzl b/tools/cpp/unix_cc_configure.bzl
index 588e33b..38db2fc 100644
--- a/tools/cpp/unix_cc_configure.bzl
+++ b/tools/cpp/unix_cc_configure.bzl
@@ -202,20 +202,21 @@
# If the compiler sometimes rewrites paths in the .d files without symlinks
# (ie when they're shorter), it confuses Bazel's logic for verifying all
# #included header files are listed as inputs to the action.
+ # We also rely on symlinks not being resolved for remote builds.
- # The '-fno-canonical-system-headers' should be enough, but clang does not
- # support it, so we also try '-no-canonical-prefixes' if first option does
- # not work.
+ # The '-no-canonical-prefixes' flag is enough in most cases.
+ # In case this flag is not supported (older gcc versions), we try to add
+ # '-fno-canonical-system-headers' instead.
opt = _add_compiler_option_if_supported(
repository_ctx,
cc,
- "-fno-canonical-system-headers",
+ "-no-canonical-prefixes",
)
if len(opt) == 0:
return _add_compiler_option_if_supported(
repository_ctx,
cc,
- "-no-canonical-prefixes",
+ "-fno-canonical-system-headers",
)
return opt
