Looks like clang was used to compile go and system level dylib was linked: $ otool -L `which go` /Users/ych/.gentoo/usr/bin/go: /usr/lib/libSystem.B.dylib (compatibility version 0.0.0, current version 0.0.0) /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 0.0.0, current version 0.0.0) /System/Library/Frameworks/Security.framework/Versions/A/Security (compatibility version 0.0.0, current version 0.0.0) Reproducible: Always
libSystem is like libc. How does that indicate clang was used?
Sorry I thought the link status is enough to prove system clang was used. In fact I noticed this problem because I just updated XCode Command Line Tools before emerging dev-lang/go and the emerge failed with a message telling me to accept EULA before running clang command.
Go's make.bash indeed seems to prefer Clang, fixed now.