build: cmake NAMELINK_COMPONENT in vpp libraries

Installs the unversioned .so symlink in the -dev component.
This prevent debian lintian error:
link-to-shared-library-in-wrong-package

NAMELINK_COMPONENT was added in cmake 3.12

Type: make
Change-Id: I9d743218fa1f6b677659d745525e399ff66e73f4
Signed-off-by: Nick Brown <nickbroon@gmail.com>
diff --git a/src/cmake/library.cmake b/src/cmake/library.cmake
index ad4adfc..45b3944 100644
--- a/src/cmake/library.cmake
+++ b/src/cmake/library.cmake
@@ -41,8 +41,10 @@
   endif()
   install(
     TARGETS ${lib}
-    DESTINATION ${VPP_LIBRARY_DIR}
-    COMPONENT ${ARG_COMPONENT}
+    LIBRARY
+      DESTINATION ${VPP_LIBRARY_DIR}
+      COMPONENT ${ARG_COMPONENT}
+      NAMELINK_COMPONENT ${ARG_COMPONENT}-dev
   )
 
   if (ARG_LTO AND VPP_USE_LTO)