configure: Enable clang for older OSX gcc versions

OSX often has a more recent version of clang than it does for GCC. When an older
version of gcc is detected on OSX, the --enable-clang flag is implicitly
enabled.
This commit is contained in:
Alex Crichton 2014-04-14 10:27:16 -07:00
parent 32a81d1e16
commit 682c401045

42
configure vendored
View File

@ -579,26 +579,32 @@ then
CFG_ENABLE_CLANG=1
putvar CFG_ENABLE_CLANG
else
# on OS X, with xcode 5 and newer, certain developers may have
# cc, gcc and g++ point to a mixture of clang and gcc
# if so, this will create very strange build errors
# this last stanza is to detect some such problems and save the future rust
# contributor some time solving that issue.
# this detection could be generalized to other OSes aside from OS X
# but the issue seems most likely to happen on OS X
if [ $("$CFG_GCC" --version 2>&1 | grep -c ' 4\.[0-6]') -ne 0 ]; then
step_msg "older GCC found, using clang instead"
CFG_ENABLE_CLANG=1
putvar CFG_ENABLE_CLANG
else
# on OS X, with xcode 5 and newer, certain developers may have
# cc, gcc and g++ point to a mixture of clang and gcc
# if so, this will create very strange build errors
# this last stanza is to detect some such problems and save the future rust
# contributor some time solving that issue.
# this detection could be generalized to other OSes aside from OS X
# but the issue seems most likely to happen on OS X
chk_cc () {
$1 --version 2> /dev/null | grep -q $2
}
# check that gcc, cc and g++ all point to the same compiler.
# note that for xcode 5, g++ points to clang, not clang++
if !((chk_cc gcc clang && chk_cc g++ clang) ||
(chk_cc gcc gcc &&( chk_cc g++ g++ || chk g++ gcc))) then
err "the gcc and g++ in your path point to different compilers.
Check which versions are in your path with cc --version and g++ --version.
To resolve this problem, either fix your PATH or run configure with --enable-clang"
fi
chk_cc () {
$1 --version 2> /dev/null | grep -q $2
}
# check that gcc, cc and g++ all point to the same compiler.
# note that for xcode 5, g++ points to clang, not clang++
if !((chk_cc gcc clang && chk_cc g++ clang) ||
(chk_cc gcc gcc &&( chk_cc g++ g++ || chk g++ gcc))) then
err "the gcc and g++ in your path point to different compilers.
Check which versions are in your path with cc --version and g++ --version.
To resolve this problem, either fix your PATH or run configure with --enable-clang"
fi
fi
fi