score: Avoid clash with <strings.h> provided fls()

cpukit/score/src/kern_tc.c

@@ -75,10 +75,11 @@ ISR_LOCK_DEFINE(, _Timecounter_Lock, "Timecounter")
 #define bcopy(x, y, z) memcpy(y, x, z);
 #define log(...)
 static inline int
-fls(int x)
+builtin_fls(int x)
 {
         return x ? sizeof(x) * 8 - __builtin_clz(x) : 0;
 }
+#define fls(x) builtin_fls(x)
 /* FIXME: https://devel.rtems.org/ticket/2348 */
 #define ntp_update_second(a, b) do { (void) a; (void) b; } while (0)
 #endif /* __rtems__ */