Tell clang not to report -Wpadded warnings on public headers we can't fix

Better to silence the compiler warning than break ABI.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

XKBstr.h

@@ -37,6 +37,16 @@ THE USE OR PERFORMANCE OF THIS SOFTWARE.
 					  (int)(((h)<<8)|(l)&0x7fff))
 #else
 #define	Xkb2CharsToInt(h,l)	((short)(((h)<<8)|(l)))
+#endif
+
+/*
+ * The Xkb structs are full of implicit padding to properly align members.
+ * We can't clean that up without breaking ABI, so tell clang not to bother
+ * complaining about it.
+ */
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wpadded"
 #endif
 
 	/*
@@ -610,4 +620,8 @@ typedef struct _XkbDeviceChanges {
 	XkbDeviceLedChangesRec 	leds;
 } XkbDeviceChangesRec,*XkbDeviceChangesPtr;
 
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+
 #endif /* _XKBSTR_H_ */