<rdar://problem/13200878>

When launching in the shell, make sure if you specify a relative path, and if the current working directory has a space in it, that we don't hose the shell invocation.

Currently if we launch with a relative path, we prepend the current working directory to the PATH using:

PATH=`cwd`:$PATH a.out ...

We needed to add quotes around the value for PATH to make sure if any paths in PATH contained spaces, that we don't hose the shell command. Now we do a:

PATH="`cwd`:$PATH" a.out ...

llvm-svn: 175135