ref: defa95dda51decece13ccda08394a9b2f73bec4d
dir: /m4/optional-fmt.m4/
dnl $1 package name e.g. flac
dnl $2 package name in conditionals e.g. FLAC
dnl $3 using check
AC_DEFUN([AC_OPTIONAL_FORMAT],
[AC_ARG_WITH($1, AC_HELP_STRING([--with-$1=dyn], [load $1 dynamically]))
using_$1=$with_$1
if test "_$with_$1" = _dyn; then
if test $using_libltdl != yes; then
AC_MSG_FAILURE([not using libltdl; cannot load $1 dynamically])
fi
elif test "_$with_$1" = _; then
using_$1=$opt_default
elif test "_$with_$1" != _yes -a "_$with_$1" != _no; then
AC_MSG_FAILURE([invalid selection --with-$1=$with_$1])
fi
if test _$with_$1 != _no; then
$3
if test _$with_$1 != _ -a $using_$1 = no; then
AC_MSG_FAILURE([cannot find $1])
fi
fi
if test "$using_$1" != no; then
AC_DEFINE(HAVE_$2, 1, [Define to 1 if you have $1.])
if test "$using_$1" = yes; then
AC_DEFINE(STATIC_$2, 1, [Define to 1 if you have static $1.])
fi
fi
AM_CONDITIONAL(HAVE_$2, test $using_$1 != no)
AM_CONDITIONAL(STATIC_$2, test $using_$1 = yes)
AC_SUBST($2_CFLAGS)
AC_SUBST($2_LIBS)]
)