Instead of doing the awkward /bin path prepending at config.site
creation time, set darwin_{CC,CXX} in a way that fully determines the
program's path (clang/clang++) similar to how AC_PATH_{TOOL,PROG} would
do.
Also see the added comment block in depends/Makefile for more context on
determining $PATH for our config.site.
clang warns when a command line option is unused, and some of our tests
use Werror, so unfortunately we cannot use this flag to pin our linker
for now. Leaving this commit in for future reference, as it would be
great if there's more granularity to Werror and we can be explicit about
what linker we want to use.
For depends builds this was fixed by fbcfcf69, which deleted the conflicting
headers. When we no longer control the clang installation, we need to ensure
that the SDK's libc++ headers are used rather than the ones shipped with clang.
We can do that by turning off the default include path and hard-coding our own.
This hard-coded path is ok because we control (via SDK packaging) where these
headers end-up.
Side-note: Now that this path is hard-coded in depends, we can potentially
package the SDK differently, as the c++ folder can live wherever is most
convenient for us.
tl;dr: Update to the newer stable toolchain and SDK for OSX without giving up
any backwards compatibility. We can move to clang 3.5 as a next step which
allows use to use libc++ and the 10.10 sdk, but we'll need to find a build that
works in gitian/travis first.
Switch to a new, better maintained fork of cctools:
https://github.com/tpoechtrager/cctools-port
I've forked this and will be working on it some as well:
https://github.com/theuni/cctools-port
This brings in:
cctools v862
ld64: v241.9
It also fixes 64bit builds, so there's no longer any need to use a 32bit clang.
Since clang is no longer tied to an old/crusty 32bit build, clang has been
upgraded to 3.3. Unfortunately, there's a bug in 3.4 that breaks builds. 3.5
works fine, but there are no binary builds compatible with precise, which is
currently used for gitian and travis. We could always build our own if
necessary.
After updating to stable clang/linker/cctools, it's possible to use a more
recent SDK. The current SDK (10.7) through the most recent 10.10 have all been
built/tested successfully, both with and without 10.6 compatibility. However,
10.10 requires clang 3.5.
SDKs >= 10.9 use libc++ rather than libstdc++. This is verified working as well.
Carl Dong