checking Mac OS X headers

[Vincent Torri]

Hey,

I would like to check if some Mac OS X headers are available. So I first 
set the Objective C compiler with AC_LANG_PUSH, only if there is an 
Objective C compiler:

# Check compilers

m4_ifdef([AC_PROG_OBJC],
   [
    AC_PROG_OBJC
    _AM_DEPENDENCIES(OBJC)
   ],
   [
    AC_CHECK_TOOL([OBJC], [gcc])
    AC_SUBST([OBJC])
    AC_SUBST([OBJCFLAGS])
   ]
)
AC_PROG_CXX
AC_PROG_CC

# check header

m4_ifdef([AC_PROG_OBJC], [AC_LANG_PUSH([Objective C])], [])
AC_CHECK_HEADERS([/System/Library/Frameworks/Cocoa.framework/Headers/Cocoa.h],
   [have_dep="yes"],
   [have_dep="no"])
m4_ifdef([AC_PROG_OBJC], [AC_LANG_POP([Objective C])], [])

But the configure script fails:

configure: error: in `/home/torri/svnroot/evas':
configure: error: Objective C preprocessor "/lib/cpp" fails sanity check

I have looked at config.log but it does not help a lot.

Does someone see where I'm wrong ?

thank you

Vincent Torri