target_include_directories move out from if(NOT EMCC) block.

src/CMakeLists.txt

@@ -26,12 +26,12 @@ ExternalProject_Add(
 endif()
 
 add_library(protos ${SRCs})
+target_include_directories(protos PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 
 if (NOT EMCC)
 target_link_libraries(protos
   avformat avcodec avdevice avfilter avutil
   swresample swscale postproc z x264 lzma)
-target_include_directories(protos PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 endif()
 
 install(TARGETS protos