could not build module foundation

今天新建工程，突然发现爆出could not build module foundation的bug，就是运行不了,clean也没用。

在网站

http://stackoverflow.com/questions/19723392/adding-c-file-causes-pch-error

找到解决方案，说是

Surround #import's with preprocessor directive #ifdef __OBJC__ #endif

Thanks! That was it. I think I figured out why this works: the pch is included as a prefix into both C and ObjC files. So my C files were getting Foundation.h which of course would never work


我的问题也是在内部同时导入了c和oc头文件，我尝试注释掉c文件的引用，ok，能够build运行了，

貌似是既有c文件又有oc文件会出这个问题，但我取消注释后，又没事了，纳闷。