CFLAGS for AC_COMPILE_IFELSE.

[Edward Tomasz Napierala]

I need the configure script to figure out how many parameters one particular
library function requires, due to API change.  I've found a macro to do that,
it looks like this:

AC_DEFUN([AC_JACK_MIDI_NFRAMES_CHECK], [
AC_MSG_CHECKING([whether JACK MIDI functions need nframes parameter])
AC_LANG_PUSH(C)
AC_COMPILE_IFELSE(AC_LANG_PROGRAM([[
#include <jack/jack.h>
#include <jack/midiport.h>
]], [[
jack_midi_event_get(0, 0, 0, 0);
]]), [jackmidi_nframes='yes'], [jackmidi_nframes='no'])
AC_MSG_RESULT([$jackmidi_nframes])
AC_LANG_POP()
])

Problem is, it does not work for me.  Probable reason is this
(from config.log):

configure:5138: checking whether JACK MIDI functions need nframes parameter
configure:5172: gcc -c -g -O2  conftest.c >&5
conftest.c:32:23: error: jack/jack.h: No such file or directory
conftest.c:33:27: error: jack/midiport.h: No such file or directory

It does not work, because it does not use the proper CFLAGS - this
is FreeBSD, includes live in /usr/local/include and it's neccessary
to pass -I/usr/local/include.

So, the question is, how to modify the above macro to use CFLAGS it got
(or should got) from pkg-config, for example?

-- 
If you cut off my head, what would I say?  Me and my head, or me and my body?