Fixes file extension for loadable modules on OS X.

Patch by Wesley Peck!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122395 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/cmake/modules/AddLLVM.cmake b/cmake/modules/AddLLVM.cmake
index d03b3e0..fdf1df0 100755
--- a/cmake/modules/AddLLVM.cmake
+++ b/cmake/modules/AddLLVM.cmake
@@ -36,7 +36,13 @@
     add_custom_target(${name})
   else()
     llvm_process_sources( ALL_FILES ${ARGN} )
-    add_library( ${name} MODULE ${ALL_FILES} )
+    if (MODULE)
+      set(libkind MODULE)
+    else()
+      set(libkind SHARED)
+    endif()
+
+    add_library( ${name} ${libkind} ${ALL_FILES} )
     set_target_properties( ${name} PROPERTIES PREFIX "" )
 
     if (APPLE)