When looking for executable extensions, ignore .dSYM, as that's the debug info directory on Darwin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56667 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/configure b/configure
index af8144d..8183959 100755
--- a/configure
+++ b/configure
@@ -4545,7 +4545,7 @@
   (exit $ac_status); }; then
     for file in conftest.*; do
       case $file in
-      *.c | *.o | *.obj) ;;
+      *.c | *.o | *.obj | *.dSYM) ;;
       *) ac_cv_build_exeext=`echo $file | sed -e s/conftest//` ;;
       esac
     done