LLVM linking

[mskrzypkows]

fix #7

I'm not sure if it's proper solution for #7 but it solves build break on my Ubuntu 14.04.

[emilio]

r? @larsbergstrom

It seems like that could impact our builders. Seems like a sensible solution, I guess. Thanks for looking into it! :)

[larsbergstrom]

We'd need to ask @glennw why he added --disabled-shared-llvm-libs in the first place. I don't have a big opinion myself on the build machines for whether we link against an existing LLVM installation or build our own, though I suspect that linking against the existing one would also help me with my sadly-stalled #3 :-)

[glennw]

I can't recall the exact reason for that flag - I think I was having issues with dynamic library paths on mac without it. The actual ideal solution would be to disable LLVM from the build altogether, if there is a flag for that?

For our test scenario, we specifically want to use the softpipe driver, and not the llvmpipe driver. This is because when running 10,000+ simple tests (like our CI does), the shader compile time with llvmpipe dominates, and so the tests actually run much faster with softpipe :)

Now that we use softpipe driver, it might be safe to remove this flag anyway, since we select the softpipe driver at startup time.

[glennw]

If there's no flag to disable llvmpipe from the build, let me know and I'll test this locally on mac + linux, and merge it if all works ok.

[mskrzypkows]

If there's no flag to disable llvmpipe from the build, let me know

@glennw Who will know that?

[jdm]

You could try configuring osmesa with --enable-gallium-llvm=no per https://github.com/servo/osmesa-src/blob/master/mesa-12.0.1/configure.ac#L2082 .

[mskrzypkows]

I've tested changes in configure.ac:
[enable_gallium_llvm=no]
and second try with:
[enable_llvm_shared_libs=no]
none of above code samples works.

But deleting .arg("--enable-gallium-osmesa") from build.rs and bringing back .arg("--disable-llvm-shared-libs") makes building OK.

[mskrzypkows]

Will the patch be merged?

[glennw]

@mskrzypkows I'll test with your patch on each platform next week. There was a specific reason for having that flag, so I'll need to test again on each platform before removing it. If all goes well, I'll merge it.

[emuplz]

any chance of this being merged? I'm having issues building on OSX due to a strange ncurses linker error too.