Android: Don't include Qt D-Bus by default

Recently, a dependency on Qt D-Bus was added to
Qt Platform Support if Qt was configured to support it. Since
Qt defaults to checking for Qt D-Bus at run-time, the platform
plugin and thus all applications would depend on libQt5DBus.so.

Qt D-Bus really doesn't make much sense on Android, so we default
to disabling it instead on this particular platform. People
with use cases where this might be used can still configure Qt
to include support by passing -dbus to configure.

Note that this makes OS X and Linux builds consistent with
Windows builds, where Qt D-Bus was already disabled because
the dbus.h header was missing.

Change-Id: Id733ff00918c706bf1aa5a667299e7d578b4b0c1
Task-number: QTBUG-44581
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

configure

@@ -678,7 +678,7 @@ CFG_TSLIB=auto
 CFG_NIS=auto
 CFG_CUPS=auto
 CFG_ICONV=auto
-CFG_DBUS=runtime
+CFG_DBUS=auto
 CFG_GLIB=auto
 CFG_QGTKSTYLE=auto
 CFG_LARGEFILE=auto
@@ -3084,6 +3084,9 @@ if ( [ "$CFG_XCB" = "system" ] || [ "$CFG_XCB" = "qt" ] ) && [ "$CFG_XKBCOMMON"
 fi
 
 if [ "$XPLATFORM_ANDROID" = "yes" ]; then
+    if [ "$CFG_DBUS" = "auto" ]; then
+        CFG_DBUS="no"
+    fi
     if [ -z "$CFG_DEFAULT_ANDROID_NDK_HOST" ]; then
         case $PLATFORM in
         linux-*)
@@ -4867,6 +4870,9 @@ if [ "$CFG_ICONV" != "no" ]; then
 fi
 
 # auto-detect libdbus-1 support
+if [ "$CFG_DBUS" = "auto" ]; then
+    CFG_DBUS="runtime"
+fi
 if [ "$CFG_DBUS" = "linked" ]; then
     if [ -n "$PKG_CONFIG" ] && $PKG_CONFIG --atleast-version="$MIN_DBUS_1_VERSION" dbus-1 2>/dev/null; then
         QT_CFLAGS_DBUS=`$PKG_CONFIG --cflags dbus-1 2>/dev/null`