configure: Colorize output

If we're running from a TTY we can put some colors around 'yes',
'no' and other messages.

Shamelessly copied from Ruby source code and modified a bit to
comply with syntax-check.

https://github.com/ruby/ruby/commit/e4879592873abd4cd8aeed56f4cbaa360a3d3736Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

m4/virt-colours.m4

+dnl Colourful configure
+dnl
+dnl Copyright (C) 2015 Nobuyoshi Nakada
+dnl
+dnl This library is free software; you can redistribute it and/or
+dnl modify it under the terms of the GNU Lesser General Public
+dnl License as published by the Free Software Foundation; either
+dnl version 2.1 of the License, or (at your option) any later version.
+dnl
+dnl This library 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 GNU
+dnl Lesser General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU Lesser General Public
+dnl License along with this library.  If not, see
+dnl <http://www.gnu.org/licenses/>.
+
+AC_DEFUN([_COLORIZE_RESULT_PREPARE], [
+    msg_checking= msg_result_yes= msg_result_no= msg_result_other= msg_reset=
+    AS_IF([test -t 1], [
+	msg_begin="`tput smso 2>/dev/null`"
+	AS_CASE(["$msg_begin"], ['@<:@'*m],
+	    [msg_begin="`echo "$msg_begin" | sed ['s/[0-9]*m$//']`"
+	    msg_checking="${msg_begin}33m"
+	    AS_IF([test ${TEST_COLORS:+set}], [
+		msg_result_yes=[`expr ":$TEST_COLORS:" : ".*:pass=\([^:]*\):"`]
+		msg_result_no=[`expr ":$TEST_COLORS:" : ".*:fail=\([^:]*\):"`]
+		msg_result_other=[`expr ":$TEST_COLORS:" : ".*:skip=\([^:]*\):"`]
+	    ])
+	    msg_result_yes="${msg_begin}${msg_result_yes:-32;1}m"
+	    msg_result_no="${msg_begin}${msg_result_no:-31;1}m"
+	    msg_result_other="${msg_begin}${msg_result_other:-33;1}m"
+	    msg_reset="${msg_begin}m"
+	    ])
+	AS_UNSET(msg_begin)
+	])
+    AS_REQUIRE_SHELL_FN([colorize_result],
+	[AS_FUNCTION_DESCRIBE([colorize_result], [MSG], [Colorize result])],
+        [AS_CASE(["$[]1"],
+            [yes], [AS_ECHO(["${msg_result_yes}$[]1${msg_reset}]")],
+            [no], [AS_ECHO(["${msg_result_no}$[]1${msg_reset}]")],
+            [AS_ECHO(["${msg_result_other}$[]1${msg_reset}]")])])
+])
+
+AC_DEFUN([COLORIZE_RESULT], [AC_REQUIRE([_COLORIZE_RESULT_PREPARE])dnl
+    AS_LITERAL_IF([$1],
+	[m4_case([$1],
+		[yes], [AS_ECHO(["${msg_result_yes}$1${msg_reset}"])],
+		[no], [AS_ECHO(["${msg_result_no}$1${msg_reset}"])],
+		[AS_ECHO(["${msg_result_other}$1${msg_reset}"])])],
+	[colorize_result "$1"]) dnl
+])
+
+AC_DEFUN([AC_CHECKING],[dnl
+AC_REQUIRE([_COLORIZE_RESULT_PREPARE])dnl
+AS_MESSAGE([checking ${msg_checking}$1${msg_reset}...])])
+
+AC_DEFUN([AC_MSG_RESULT], [dnl
+{ _AS_ECHO_LOG([result: $1])
+COLORIZE_RESULT([$1]); dnl
+}])