cmake: add vapi build

Change-Id: Id939a0cbe35601478ad262f49bb0a1abdb62aa45
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/cmake/library.cmake b/src/cmake/library.cmake
index 6aa0ae8..9ed53e9 100644
--- a/src/cmake/library.cmake
+++ b/src/cmake/library.cmake
@@ -33,7 +33,7 @@
   endif()
 
   if(ARG_API_FILES)
-    vpp_add_api_files(${lib}_api_headers ${ARG_API_FILES})
+    vpp_add_api_files(${lib} ${ARG_API_FILES})
     foreach(file ${ARG_API_FILES})
       get_filename_component(dir ${file} DIRECTORY)
       install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${file}.h DESTINATION include/${lib}/${dir})