libffi

[Curtis Matz]

I’ve installed libffi but I’m trying to compile and it says it can’t find ffi.h.  How do I tell my compiler which happens to be gcc9 to look in /opt/local for the header file?

> port installed | grep libffi
  libffi @3.2.1_0 (active)

src/rtlib/thread_call.c:33:10: fatal error: ffi.h: No such file or directory
   33 | #include <ffi.h>
      |          ^~~~~~~
compilation terminated.
make: *** [src/rtlib/obj/darwin-x86_64/thread_call.o] Error 1

> which gcc
/opt/local/bin/gcc
> gcc --version
gcc (MacPorts gcc9 9.3.0_1) 9.3.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.