Add parameter to allow enabling/disabling selftests via configure

This is a follow-up of:

  https://sourceware.org/ml/gdb-patches/2018-08/msg00347.html

Instead of going throttle and always enabling our selftests (even in
non-development builds), this patch is a bit more conservative and
introduces a configure option ("--enable-unit-tests") that allows the
user to choose whether she wants unit tests in the build or not.  Note
that the current behaviour is retained: if no option is provided, GDB
will have selftests included in a development build, and will *not*
have selftests included in a non-development build.

The rationale for having this option is still the same: due to the
many racy testcases and random failures we see when running the GDB
testsuite, it is unfortunately not possible to perform a full test
when one is building a downstream package.  As the Fedora GDB
maintainer and one of the Debian GDB uploaders, I feel like this
situation could be improved by, at least, executing our selftests
after the package has been built.

This patch introduces no regressions to our build.

OK?

gdb/ChangeLog:
2018-10-10  Sergio Durigan Junior  <sergiodj@redhat.com>
	    Simon Marchi <simark@simark.ca>

	* README (`configure' options): Add documentation for new
	"--enable-unit-tests" option.
	* acinclude.m4: Include "selftest.m4".
	* configure: Regenerate.
	* configure.ac: Use "GDB_AC_SELFTEST".
	* maint.c (maintenance_selftest): Update message informing
	that selftests have been disabled.
	(maintenance_info_selftests): Likewise.
	* selftest.m4: New file.

gdb/gdbserver/ChangeLog:
2018-10-10  Sergio Durigan Junior  <sergiodj@redhat.com>
	    Simon Marchi <simark@simark.ca>

	* acinclude.m4: Include "../selftest.m4".
	* configure: Regenerate.
	* configure.ac: Use "GDB_AC_SELFTEST".
	* configure.srv: Use "$enable_unittests" instead of
	"$development" when checking whether unit tests have been
	enabled.
	* server.c (captured_main): Update message informing that
	selftests have been disabled.

gdb/testsuite/ChangeLog:
2018-10-10  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.gdb/unittest.exp: Update expected message informing that
	selftests have been disabled.
	* gdb.server/unittest.exp: Likewise.

squash! Add parameter to allow enabling/disabling selftests via configure

1 files changed, 45 insertions, 0 deletions

diff --git a/gdb/selftest.m4 b/gdb/selftest.m4
new file mode 100644
index 00000000000..acf4050bde8
--- /dev/null
+++ b/gdb/selftest.m4
@@ -0,0 +1,45 @@
+dnl Copyright (C) 2018 Free Software Foundation, Inc.
+dnl
+dnl This file is part of GDB.
+dnl
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 3 of the License, or
+dnl (at your option) any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+dnl GNU General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+dnl GDB_AC_SELFTEST(ACTION-IF-ENABLED)
+dnl
+dnl Enable the unit/self tests if needed.  If they are enabled, AC_DEFINE
+dnl the GDB_SELF_TEST macro, and execute ACTION-IF-ENABLED.
+
+AC_DEFUN([GDB_AC_SELFTEST],[
+# Check whether we will enable the inclusion of unit tests when
+# compiling GDB.
+#
+# The default value of this option changes depending whether we're on
+# development mode (in which case it's "true") or not (in which case
+# it's "false").
+AC_ARG_ENABLE(unit-tests,
+AS_HELP_STRING([--enable-unit-tests],
+[Enable the inclusion of unit tests when compiling GDB]),
+[case "${enableval}" in
+  yes)  enable_unittests=true  ;;
+  no)   enable_unittests=false ;;
+  *)    AC_MSG_ERROR(
+[bad value ${enableval} for --{enable,disable}-unit-tests option]) ;;
+esac], [enable_unittests=$development])
+
+if $enable_unittests; then
+  AC_DEFINE(GDB_SELF_TEST, 1,
+            [Define if self-testing features should be enabled])
+  $1
+fi
+])