clang-3.3 @3.3-r173279 AddressSanitizer binaries don't work without explicitly setting DYLD_LIBRARY_PATH

[acmorrow (Andrew C. Morrow)]

I'm using clang-3.3 @3.3-r173279:

> /opt/local/bin/clang-mp-3.3 --version
clang version 3.3 (trunk 173279)
Target: x86_64-apple-darwin12.3.0
Thread model: posix

Given a simple hello world C++ program compiled with -fsanitize=address, the resulting binary cannot execute.

>  cat ./hello_world.cpp
#include <cstdlib>
#include <iostream>

int main(int argc, char* argv[]) {
  std::cout << "Hello, World!\n";
  return EXIT_SUCCESS;
}
>  /opt/local/bin/clang-mp-3.3 ./hello_world.cpp -fsanitize=address -o ./hello_world
>  ./hello_world
dyld: Library not loaded: /opt/local/var/macports/build/_opt_mports_dports_lang_llvm-3.3/clang-3.3/work/trunk/Release+Debug+Asserts/lib/clang/3.3/lib/darwin/libclang_rt.asan_osx_dynamic.dylib
  Referenced from: hello_world/./hello_world
  Reason: image not found
[1]    62828 trace trap  ./hello_world

It looks as if it is looking for the asan support library in the original build path, not the install path. But we do find that library in the install for the port:

>  mdfind -name libclang_rt.asan_osx_dynamic.dylib
/opt/local/libexec/llvm-3.3/lib/clang/3.3/lib/darwin/libclang_rt.asan_osx_dynamic.dylib

Adding the containing directory to the DYLD_LIBRARY_PATH fixes things: the binary now runs:

>  DYLD_LIBRARY_PATH=/opt/local/libexec/llvm-3.3/lib/clang/3.3/lib/darwin ./hello_world
Hello, World!

AddressSanitizer is super useful, it would be great if it worked out of the box for macports clang.