fbcode_builder: use build interface generator expression for thrift include directories

Summary:
Fix an error about source directories being included in the include
path in add_thrift_cpp2_library. I don't know why this was failing for
fb303 and not for other projects, but adding a generation expression
appears to fix the issue.

Reviewed By: strager

Differential Revision: D15725024

fbshipit-source-id: 6c02fed6c6703733cf9e0b130c0f90b70e3ea300

build/fbcode_builder/CMake/ThriftCppLibrary.cmake

@@ -105,8 +105,8 @@ function(add_thrift_cpp2_library LIB_NAME THRIFT_FILE)
   target_include_directories(
     ${LIB_NAME}
     PUBLIC
-      ${CMAKE_SOURCE_DIR}
-      ${CMAKE_BINARY_DIR}
+      $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}>
+      $<BUILD_INTERFACE:${CMAKE_BINARY_DIR}>
       ${FOLLY_INCLUDE_DIR}
       ${FBTHRIFT_INCLUDE_DIR}
   )