dnl This file is stolen in its entirety from freeciv-1.8.1

dnl FC_CHECK_X_LIB(LIBRARY, FUNCTION [, ACTION-IF-FOUND [,
dnl   ACTION-IF-NOT-FOUND]])
dnl
dnl This macro is intended to search for X11-related libraries.  It takes the
dnl following variables for input:
dnl   X_LIBS		-- prefixed to all linker lines
dnl   X_EXTRA_LIBS	-- suffixed to all linker lines
dnl   LIBS		-- suffixed to all linker lines (after X_EXTRA_LIBS)
dnl Thus, the trial linker line will be "$X_LIBS -l$1 $X_EXTRA_LIBS $LIBS".
dnl
dnl The following variables are output:
dnl   X_EXTRA_LIBS	-- contains "-l$1 $X_EXTRA_LIBS" if the link succeeds
dnl
dnl Thus, the intended usage of this macro is something like this:
dnl   AC_PATH_XTRA
dnl   X_LIBS="$X_LIBS $X_PRE_LIBS"
dnl	dnl Is it just me or is AC_PATH_XTRA broken?
dnl   FC_CHECK_X_LIB(X11, XOpenDisplay, , AC_MSG_ERROR("Need X11"))
dnl   FC_CHECK_X_LIB(Xext, XShapeCombineMask)
dnl     [etc.]
dnl   LIBS="$X_LIBS $X_EXTRA_LIBS $LIBS"
dnl
AC_DEFUN(FC_CHECK_X_LIB,
[AC_MSG_CHECKING([for $2 in X library -l$1])
dnl Use a cache variable name containing both the library and function name,
dnl because the test really is for library $1 defining function $2, not
dnl just for library $1.  Separate tests with the same $1 and different $2s
dnl may have different results.
ac_lib_var=`echo $1['_']$2 | sed 'y%./+-%__p_%'`
AC_CACHE_VAL(ac_cv_lib_$ac_lib_var,
[ac_save_LIBS="$LIBS"
LIBS="$X_LIBS -l$1 $X_EXTRA_LIBS $LIBS"
AC_TRY_LINK(dnl
ifelse([$2], [main], , dnl Avoid conflicting decl of main.
[/* Override any gcc2 internal prototype to avoid an error.  */
]ifelse(AC_LANG, CPLUSPLUS, [#ifdef __cplusplus
extern "C"
#endif
])dnl
[/* We use char because int might match the return type of a gcc2
    builtin and then its argument prototype would still apply.  */
char $2();
]),
	    [$2()],
	    eval "ac_cv_lib_$ac_lib_var=yes",
	    eval "ac_cv_lib_$ac_lib_var=no")
LIBS="$ac_save_LIBS"
])dnl
if eval "test \"`echo '$ac_cv_lib_'$ac_lib_var`\" = yes"; then
  AC_MSG_RESULT(yes)
  ifelse([$3], ,
[changequote(, )dnl
  ac_tr_lib=HAVE_LIB`echo $1 | sed -e 's/[^a-zA-Z0-9_]/_/g' \
    -e 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/'`
changequote([, ])dnl
  AC_DEFINE_UNQUOTED($ac_tr_lib)
  X_EXTRA_LIBS="-l$1 $X_EXTRA_LIBS"
], [$3])
else
  AC_MSG_RESULT(no)
ifelse([$4], , , [$4
])dnl
fi
])


dnl FC_EXPAND_DIR(VARNAME, DIR)
dnl expands occurrences of ${prefix} and ${exec_prefix} in the given DIR,
dnl and assigns the resulting string to VARNAME
dnl example: FC_EXPAND_DIR(LOCALEDIR, "$datadir/locale")
dnl eg, then: AC_DEFINE_UNQUOTED(LOCALEDIR, "$LOCALEDIR")
dnl by Alexandre Oliva 
dnl from http://www.cygnus.com/ml/automake/1998-Aug/0040.html
AC_DEFUN(FC_EXPAND_DIR, [
        $1=$2
        $1=`(
            test "x$prefix" = xNONE && prefix="$ac_default_prefix"
            test "x$exec_prefix" = xNONE && exec_prefix="${prefix}"
            eval echo \""[$]$1"\"
        )`
])


dnl FC_XPM_PATHS
dnl Allow user to specify extra include/lib paths for Xpm, with
dnl --with-xpm=prefix  --with-xpm-lib=dir  --with-xpm-include=dir
dnl The latter two override the prefix form.
dnl Sets variables xpm_libdir and xpm_incdir
dnl If user supplies a path, use that.
dnl If user specifies "no", set that, meaning "no extra path"
dnl If user specifies "yes" (default), then use /usr/local if it looks
dnl likely, else set to "no".
dnl Doesn't do any cache stuff.
dnl
AC_DEFUN(FC_XPM_PATHS,
[AC_MSG_CHECKING(extra paths for Xpm)
dnl General Xpm prefix:
dnl "no" means no prefix is required, "yes" means try /usr/local
AC_ARG_WITH(xpm-prefix,
    [  --with-xpm-prefix=DIR   Xpm files are in DIR/lib and DIR/include,
                          or use the following to set them separately:],
    xpm_prefix="$withval", 
    xpm_prefix="yes"
)
if test "$xpm_prefix" = "yes" || test "$xpm_prefix" = "no"; then
    xpm_libdir="$xpm_prefix"
    xpm_incdir="$xpm_prefix"
else
    xpm_libdir="$xpm_prefix/lib"
    xpm_incdir="$xpm_prefix/include"
fi
dnl May override general Xpm prefix with explicit individual paths:
AC_ARG_WITH(xpm-lib,
    [  --with-xpm-lib=DIR      Xpm library is in DIR],
    xpm_libdir="$withval" 
)
AC_ARG_WITH(xpm-include,
    [  --with-xpm-include=DIR  Xpm header file is in DIR (that is, DIR/X11/xpm.h)],
    xpm_incdir="$withval" 
)
dnl If xpm-lib path was not specified, try /usr/local/lib if that 
dnl looks likely; we don't actually try to link.
fc_xpm_default=/usr/local
if test "$xpm_libdir" = "yes"; then
    xpm_libdir="no"
    fc_xpm_default_lib="$fc_xpm_default/lib"
    for fc_extension in a so sl; do
        if test -r $fc_xpm_default_lib/libXpm.$fc_extension; then
            xpm_libdir=$fc_xpm_default_lib
            break
        fi
    done
fi
dnl Likewise for xpm-include with /usr/local/include;
dnl we don't actually try to include.
if test "$xpm_incdir" = "yes"; then
    xpm_incdir="no"
    fc_xpm_default_inc="no"
    if test -r $fc_xpm_default_inc/X11/xpm.h; then
        xpm_incdir=$fc_xpm_default_inc
    fi
fi
AC_MSG_RESULT([library $xpm_libdir, include $xpm_incdir])
])