make some headers public

templates/CMakeLists.txt.template

@@ -514,8 +514,8 @@
   % endfor
 
   target_include_directories(${lib.name}
+    PUBLIC <%text>$<INSTALL_INTERFACE:include> $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include></%text>
     PRIVATE <%text>${CMAKE_CURRENT_SOURCE_DIR}</%text>
-    PRIVATE <%text>${CMAKE_CURRENT_SOURCE_DIR}</%text>/include
     PRIVATE <%text>${BORINGSSL_ROOT_DIR}</%text>/include
     PRIVATE <%text>${PROTOBUF_ROOT_DIR}</%text>/src
     PRIVATE <%text>${ZLIB_INCLUDE_DIR}</%text>