Fixed potential FTBFS in htmlattrs.c. This relates to bug 2850.

The FTBFS seems to happen only for some users, so this fix should help
in such cases.

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
(cherry picked from commit 6629107ba8)

khtml/misc/htmlattrs.c

@@ -825,8 +825,9 @@ static const short lookup[] =
 
 #ifdef __GNUC__
 __inline
-#ifdef __GNUC_STDC_INLINE__
+#else
-__attribute__ ((__gnu_inline__))
+#ifdef __cplusplus
+inline
 #endif
 #endif
 const struct attrs *