Edit: /usr/share/aclocal-1.11/make.m4 (1367B)
# Check to see how 'make' treats includes. -*- Autoconf -*-
# Copyright (C) 2001, 2002, 2003, 2005, 2009 Free Software Foundation, Inc.
#
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
# serial 4
# AM_MAKE_INCLUDE()
# -----------------
# Check to see how make treats includes.
AC_DEFUN([AM_MAKE_INCLUDE],
[am_make=${MAKE-make}
cat > confinc << 'END'
am__doit:
@echo this is the am__doit target
.PHONY: am__doit
END
# If we don't find an include directive, just comment out the code.
AC_MSG_CHECKING([for style of include used by $am_make])
am__include="#"
am__quote=
_am_result=none
# First try GNU make style include.
echo "include confinc" > confmf
# Ignore all kinds of additional output from `make'.
case `$am_make -s -f confmf 2> /dev/null` in #(
*the\ am__doit\ target*)
am__include=include
am__quote=
_am_result=GNU
;;
esac
# Now try BSD make style include.
if test "$am__include" = "#"; then
echo '.include "confinc"' > confmf
case `$am_make -s -f confmf 2> /dev/null` in #(
*the\ am__doit\ target*)
am__include=.include
am__quote="\""
_am_result=BSD
;;
esac
fi
AC_SUBST([am__include])
AC_SUBST([am__quote])
AC_MSG_RESULT([$_am_result])
rm -f confinc confmf
])