Test for mtdev before assuming multitouch

If the XI2.2 headers are present but mtdev isn't, build without MULTITOUCH
defined.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

configure.ac

@@ -48,13 +48,14 @@ XORG_DEFAULT_OPTIONS
 PKG_CHECK_MODULES(XORG, [xorg-server >= 1.10] xproto inputproto)
 PKG_CHECK_MODULES(UDEV, udev)
 
-PKG_CHECK_MODULES(XI22, [inputproto >= 2.1.99.3],
-                  HAVE_XI22="yes"; AC_DEFINE(MULTITOUCH, 1, [XI2.2 available]),
-                  HAVE_XI22="no")
+PKG_CHECK_MODULES(XI22, [inputproto >= 2.1.99.3], HAVE_XI22="yes", HAVE_XI22="no")
 
 if test "x$HAVE_XI22" = xyes; then
         # Obtain compiler/linker options for mtdev
-        PKG_CHECK_MODULES(MTDEV, mtdev)
+        PKG_CHECK_MODULES(MTDEV, mtdev, HAVE_MTDEV="yes", HAVE_MTDEV="no")
+fi
+if test "x$HAVE_XI22" = xyes && test "x$HAVE_MTDEV" = xyes; then
+        AC_DEFINE(MULTITOUCH, 1, [XI2.2 available])
 fi
 
 # Define a configure option for an alternate input module directory