ax_with_prog.m4

# ===========================================================================
#       https://www.gnu.org/software/autoconf-archive/ax_with_prog.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_WITH_PROG([VARIABLE],[program],[VALUE-IF-NOT-FOUND],[PATH])
#
# DESCRIPTION
#
#   Locates an installed program binary, placing the result in the precious
#   variable VARIABLE. Accepts a present VARIABLE, then --with-program, and
#   failing that searches for program in the given path (which defaults to
#   the system path). If program is found, VARIABLE is set to the full path
#   of the binary; if it is not found VARIABLE is set to VALUE-IF-NOT-FOUND
#   if provided, unchanged otherwise.
#
#   A typical example could be the following one:
#
#     AX_WITH_PROG(PERL,perl)
#
#   NOTE: This macro is based upon the original AX_WITH_PYTHON macro from
#   Dustin J. Mitchell <dustin@cs.uchicago.edu>.
#
# LICENSE
#
#   Copyright (c) 2008 Francesco Salvestrini <salvestrini@users.sourceforge.net>
#   Copyright (c) 2008 Dustin J. Mitchell <dustin@cs.uchicago.edu>
#
#   Copying and distribution of this file, with or without modification, are
#   permitted in any medium without royalty provided the copyright notice
#   and this notice are preserved. This file is offered as-is, without any
#   warranty.

#serial 17

AC_DEFUN([AX_WITH_PROG],[
    AC_PREREQ([2.61])

    pushdef([VARIABLE],$1)
    pushdef([EXECUTABLE],$2)
    pushdef([VALUE_IF_NOT_FOUND],$3)
    pushdef([PATH_PROG],$4)

    AC_ARG_VAR(VARIABLE,Absolute path to EXECUTABLE executable)

    AS_IF(test -z "$VARIABLE",[
        AC_MSG_CHECKING(whether EXECUTABLE executable path has been provided)
        AC_ARG_WITH(EXECUTABLE,AS_HELP_STRING([--with-EXECUTABLE=[[[PATH]]]],absolute path to EXECUTABLE executable), [
            AS_IF([test "$withval" != yes && test "$withval" != no],[
                VARIABLE="$withval"
                AC_MSG_RESULT($VARIABLE)
            ],[
                VARIABLE=""
                AC_MSG_RESULT([no])
                AS_IF([test "$withval" != no], [
                  AC_PATH_PROG([]VARIABLE[],[]EXECUTABLE[],[]VALUE_IF_NOT_FOUND[],[]PATH_PROG[])
                ])
            ])
        ],[
            AC_MSG_RESULT([no])
            AC_PATH_PROG([]VARIABLE[],[]EXECUTABLE[],[]VALUE_IF_NOT_FOUND[],[]PATH_PROG[])
        ])
    ])

    popdef([PATH_PROG])
    popdef([VALUE_IF_NOT_FOUND])
    popdef([EXECUTABLE])
    popdef([VARIABLE])
])