Add in version dependency checks on all the tools we depend on. This is

Add in version dependency checks on all the tools we depend on. This is
necessary to ensure that a consistent configuration is created on each
platform. Certain definitions we use (like m4/libtool.m4) require certain
versions of the tools and we can no longer be slack about this or we'll
have problems with mis-configured builds.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16412 91177308-0d34-0410-b5e6-96231b3b80d8