Modernize some low-hanging PathV1 uses.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183903 91177308-0d34-0410-b5e6-96231b3b80d8
Teach clang about the armv4/armv4t distinction

When choosing a default CPU, clang used to pick ARM7TDMI (which has Thumb) even
when the more restrictive armv4 triple was specified. This should fix that.

Patch by Jeroen Hofstee.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183905 91177308-0d34-0410-b5e6-96231b3b80d8
Use version of DisplayGraph that takes a StringRef.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183916 91177308-0d34-0410-b5e6-96231b3b80d8
InheritViz.cpp uses sys::Path, include PathV1.h

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183922 91177308-0d34-0410-b5e6-96231b3b80d8