Clarify Ubuntu clang installation

[jayvdb]

On Ubuntu trusty, libclang1 is version 3.4, which is correct.

The current information about libclang1 should very clearly say it only applies to Ubuntu trusty.

However, on precise, and on xenial and later, libclang1 is not version 3.4. On Xenial it is 3.8, which doesnt work with coala. And there is no Ubuntu xenial package which is 3.4.

On xenial and later, the only way to install 3.4 is to install try to install clang-3.4 from http://apt.llvm.org/ .

[gaurav1911]

@jayvdb This can be resolved by making symbolic link:

ln -s /usr/lib/llvm-3.8/lib/libclang.so.1 /usr/lib/libclang.so

This resolves the error: "Please ensure that your python bindings are compatible with your libclang.so version." when executing py.test

[gaurav1911]

@jayvdb what changes should i make in documentation now??

[jayvdb]

@gaurav1911 , I believe that if you use llvm-3.8, the error is "python: undefined symbol: clang_annotateTokens. Please ensure that your python bindings are compatible with your libclang.so version."

See https://travis-ci.org/jayvdb/coala/jobs/208011572

If you can prove that llvm-3.8 works with coala, I will be very happy.

[gaurav1911]

@jayvdb llvm-3.8 works with coala 😄
See: https://travis-ci.org/gaurav1911/coala/jobs/208049364

[jayvdb]

Make it happen coala/coala#3854