PNaCl: Enable MIPS in a couple of places

PNaCl: Enable MIPS in a couple of places

BUG=https://code.google.com/p/nativeclient/issues/detail?id=2275
TEST=PNaCl toolchain trybots

Committed: https://src.chromium.org/viewvc/native_client?view=rev&revision=10242

[Mark Seaborn, 2012-11-08 18:13:25]

This is not enough to allow PNaCl to target MIPS, but it's a start.  Petar,
presumably you have more patches to the PNaCl scripts to enable MIPS?  Can you
share them, please, even if they're not ready for commit?

My main motivation here was to add MIPS codegen to our default LLVM build so
that I can test an implementation of the new llvm.nacl.read.tp intrinsic.

But I also started looking at what else we would need for MIPS.

I tried adding "mips32-pc-nacl" to --enable-targets in binutils-configure, but
then binutils-make failed with:

configure: error: "unsupported target mips642-pc-nacl"
checking whether vsnprintf is declared... yes
make[1]: *** [configure-gold] Error 1

Apparently we use both of the two binutils builds from build.sh.  It's quite
confusing.

[Derek Schuff, 2012-11-09 23:34:22]

lgtm