Warn that -O4 is the same as -O3.

We error on -O5 and higher. While it is tempting to do the same for -O4, I
agree with Jordan Rose: we should warn for a release at least first.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189369 91177308-0d34-0410-b5e6-96231b3b80d8
[analyzer] Don't include Clang headers inside a namespace.

Found by Gabor Kozar!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189370 91177308-0d34-0410-b5e6-96231b3b80d8
CMake: Fix out-of-source build's symlinks.

Symlinks to clang should go in Clang's build directory, not LLVM's.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189371 91177308-0d34-0410-b5e6-96231b3b80d8
scan-build: Set CC and CXX as make variables when wrapping make builds.

Variables set in a makefile are not overridden by environment variables.
Make sure we actually override CC and CXX when using scan-build.

Patch by Steve McCoy!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189372 91177308-0d34-0410-b5e6-96231b3b80d8