[PATCH 1 of 3] tools/configure.ac: add version check for glib2

[Olaf Hering <olaf@aepfle.de>]

# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1339572293 -7200
# Node ID ea554d05821b95a7e96e4a25cbf953c5abe35aeb
# Parent  a70b35deb2b5592cc1b2363860f21bb2c7049885
tools/configure.ac: add version check for glib2

xen-unstable fails to build in a SLES10SP4 environment since a long time
because the included version of glib is slightly older than the required
glib version. According to the docs glib version 2.12 includes base64
support, but SLES10 is shipped with glib 2.8.6:

qemu-timer-common.o: In function `init_get_clock':
/usr/src/packages/BUILD/xen-4.2.25432/non-dbg/tools/qemu-xen-dir/qemu-timer-common.c:57:
undefined reference to `clock_gettime'
qga/guest-agent-commands.o: In function `qmp_guest_file_write':
qga/guest-agent-commands.c:249: undefined reference to `g_base64_decode'
qga/guest-agent-commands.o: In function `qmp_guest_file_read':
qga/guest-agent-commands.c:224: undefined reference to `g_base64_encode'
collect2: ld returned 1 exit status
make[3]: *** [qemu-ga] Error 1

Add a version check to configure to require at least glib 2.12 to build
qemu-upstream.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r a70b35deb2b5 -r ea554d05821b tools/configure.ac
--- a/tools/configure.ac
+++ b/tools/configure.ac
@@ -115,7 +115,7 @@ AX_PATH_PROG_OR_FAIL([BCC], [bcc])
 AX_PATH_PROG_OR_FAIL([IASL], [iasl])
 AX_CHECK_UUID
 AX_CHECK_CURSES
-PKG_CHECK_MODULES(glib, glib-2.0)
+PKG_CHECK_MODULES(glib, [glib-2.0 >= 2.12])
 
 # Check library path
 AX_DEFAULT_LIB