This seemed like the cleanest way to find the test executable.  Also fix
the file mode.

llvm-svn: 180770

That seems to interact poorly with the environ and _environ macros
defined in MSVC's <stdlib.h>.

Also remove the incorrect comment about _NSGetEnviron().

llvm-svn: 180200

This was r180041 and r180046, which was reverted in r180066.
Re-committing this should fix the dragonegg bootstrap, which I presume
needs LD_LIBRARY_PATH to be propagated to the child.

Tested on Linux, Windows, and Mac OS 10.6.

llvm-svn: 180099

Revert "[Support] Propagate the environment into the test child process"

This reverts commit r180046.
This reverts commit r180041.

These have broken buildbots for ~3 hours:

http://lab.llvm.org:8013/builders/clang-x86_64-darwin11-nobootstrap-RAincremental/builds/763

llvm-svn: 180066

Pointed out by Eli.  The test passes for me either way, so I missed
this.

llvm-svn: 180046

Should fix the dragonegg bootstrap builder, which reasonably needs
LD_LIBRARY_PATH to be set.

llvm-svn: 180041

Summary:
This is http://llvm.org/PR15802.  Backslashes preceding double quotes in
arguments must be escaped.  The interesting bit is that all other
backslashes should *not* be escaped, because the un-escaping logic is
only triggered by the presence of a double quote character.

Reviewers: Bigcheese

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D705

llvm-svn: 180035