Tweak FindExecutable so that relative executable paths work as well.

llvm-svn: 74645
diff --git a/llvm/lib/Support/SystemUtils.cpp b/llvm/lib/Support/SystemUtils.cpp
index 5dcd334..c8c3238 100644
--- a/llvm/lib/Support/SystemUtils.cpp
+++ b/llvm/lib/Support/SystemUtils.cpp
@@ -43,9 +43,10 @@
 #undef FindExecutable   // needed on windows :(
 sys::Path llvm::FindExecutable(const std::string &ExeName,
                                const std::string &ProgramPath) {
-  // First check if the given name is a fully qualified path to an executable
+  // First check if the given name is already a valid path to an executable.
   sys::Path Result(ExeName);
-  if (Result.isAbsolute() && Result.canExecute())
+  Result.makeAbsolute();
+  if (Result.canExecute())
     return Result;
 
   // Otherwise check the directory that the calling program is in.  We can do