dnl CF_ADD_INCDIR version: 13 updated: 2010/05/26 16:44:57
dnl -------------
dnl Add an include-directory to $CPPFLAGS.  Don't add /usr/include, since it's
dnl redundant.  We don't normally need to add -I/usr/local/include for gcc,
dnl but old versions (and some misinstalled ones) need that.  To make things
dnl worse, gcc 3.x may give error messages if -I/usr/local/include is added to
dnl the include-path).
AC_DEFUN([CF_ADD_INCDIR],
[
if test -n "$1" ; then
  for cf_add_incdir in $1
  do
	while test $cf_add_incdir != /usr/include
	do
	  if test -d $cf_add_incdir
	  then
		cf_have_incdir=no
		if test -n "$CFLAGS$CPPFLAGS" ; then
		  # a loop is needed to ensure we can add subdirs of existing dirs
		  for cf_test_incdir in $CFLAGS $CPPFLAGS ; do
			if test ".$cf_test_incdir" = ".-I$cf_add_incdir" ; then
			  cf_have_incdir=yes; break
			fi
		  done
		fi

		if test "$cf_have_incdir" = no ; then
		  if test "$cf_add_incdir" = /usr/local/include ; then
			if test "$GCC" = yes
			then
			  cf_save_CPPFLAGS=$CPPFLAGS
			  CPPFLAGS="$CPPFLAGS -I$cf_add_incdir"
			  AC_TRY_COMPILE([#include <stdio.h>],
				  [printf("Hello")],
				  [],
				  [cf_have_incdir=yes])
			  CPPFLAGS=$cf_save_CPPFLAGS
			fi
		  fi
		fi

		if test "$cf_have_incdir" = no ; then
		  CF_VERBOSE(adding $cf_add_incdir to include-path)
		  ifelse([$2],,CPPFLAGS,[$2])="$ifelse([$2],,CPPFLAGS,[$2]) -I$cf_add_incdir"

		  cf_top_incdir=`echo $cf_add_incdir | sed -e 's%/include/.*$%/include%'`
		  test "$cf_top_incdir" = "$cf_add_incdir" && break
		  cf_add_incdir="$cf_top_incdir"
		else
		  break
		fi
	  fi
	done
  done
fi
])dnl
