Avoid taking the address of a macro by checking to see if stdin is defined
or not. This allows DynamicLibrary.cpp to compile on Darwin.

llvm-svn: 33064
diff --git a/llvm/lib/System/DynamicLibrary.cpp b/llvm/lib/System/DynamicLibrary.cpp
index f0ab51b..097e8b6 100644
--- a/llvm/lib/System/DynamicLibrary.cpp
+++ b/llvm/lib/System/DynamicLibrary.cpp
@@ -167,10 +167,14 @@
 #define EXPLICIT_SYMBOL(SYM) \
    if (!strcmp(symbolName, #SYM)) return &SYM
   // Try a few well known symbols just to give lli a shot at working.
+  // Note that on some systems stdin, etc. are macros so we have to
+  // avoid attempting to take the address of a macro :)
   {
+#ifndef stdin
     EXPLICIT_SYMBOL(stdin);
     EXPLICIT_SYMBOL(stdout);
     EXPLICIT_SYMBOL(stderr);
+#endif
   }
 #undef EXPLICIT_SYMBOL