Reintroduce m4/ax_prog.javac.m4

m4/ax_prog.javac.m4

@@ -0,0 +1,79 @@
+# ===========================================================================
+#      https://www.gnu.org/software/autoconf-archive/ax_prog_javac.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PROG_JAVAC
+#
+# DESCRIPTION
+#
+#   AX_PROG_JAVAC tests an existing Java compiler. It uses the environment
+#   variable JAVAC then tests in sequence various common Java compilers. For
+#   political reasons, it starts with the free ones.
+#
+#   If you want to force a specific compiler:
+#
+#   - at the configure.in level, set JAVAC=yourcompiler before calling
+#   AX_PROG_JAVAC
+#
+#   - at the configure level, setenv JAVAC
+#
+#   You can use the JAVAC variable in your Makefile.in, with @JAVAC@.
+#
+#   *Warning*: its success or failure can depend on a proper setting of the
+#   CLASSPATH env. variable.
+#
+#   TODO: allow to exclude compilers (rationale: most Java programs cannot
+#   compile with some compilers like guavac).
+#
+#   Note: This is part of the set of autoconf M4 macros for Java programs.
+#   It is VERY IMPORTANT that you download the whole set, some macros depend
+#   on other. Unfortunately, the autoconf archive does not support the
+#   concept of set of macros, so I had to break it for submission. The
+#   general documentation, as well as the sample configure.in, is included
+#   in the AX_PROG_JAVA macro.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Stephane Bortzmeyer <[email protected]>
+#
+#   This program is free software; you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation; either version 2 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 8
+
+AU_ALIAS([AC_PROG_JAVAC], [AX_PROG_JAVAC])
+AC_DEFUN([AX_PROG_JAVAC],[
+m4_define([m4_ax_prog_javac_list],["gcj -C" guavac jikes javac])dnl
+AS_IF([test "x$JAVAPREFIX" = x],
+      [test "x$JAVAC" = x && AC_CHECK_PROGS([JAVAC], [m4_ax_prog_javac_list])],
+      [test "x$JAVAC" = x && AC_CHECK_PROGS([JAVAC], [m4_ax_prog_javac_list], [], [$JAVAPREFIX/bin])])
+m4_undefine([m4_ax_prog_javac_list])dnl
+test "x$JAVAC" = x && AC_MSG_ERROR([no acceptable Java compiler found in \$PATH])
+AX_PROG_JAVAC_WORKS
+AC_PROVIDE([$0])dnl
+])