Merge pull request #279 from stmontgomery/XCTUnwrap

XCTUnwrap API
diff --git a/cmake/modules/SwiftSupport.cmake b/cmake/modules/SwiftSupport.cmake
index cf76d93..3a28b45 100644
--- a/cmake/modules/SwiftSupport.cmake
+++ b/cmake/modules/SwiftSupport.cmake
@@ -133,7 +133,11 @@
   endif()
 
   if(AST_LIBRARY)
-    set(emit_library -emit-library)
+    if(CMAKE_SYSTEM_NAME STREQUAL Windows OR CMAKE_SYSTEM_NAME STREQUAL Darwin)
+      set(emit_library -emit-library)
+    else()
+      set(emit_library -emit-library -Xlinker -soname -Xlinker ${CMAKE_SHARED_LIBRARY_PREFIX}${target}${CMAKE_SHARED_LIBRARY_SUFFIX})
+    endif()
   endif()
   if(NOT AST_LIBRARY OR library_kind STREQUAL SHARED)
     add_custom_command(OUTPUT