Make improvements

- wcsstr() is now linearly complex
- strstr16() is now linearly complex
- strstr() is now vectorized on aarch64 (10x)
- strstr() now uses KMP on pathological cases
- memmem() is now vectorized on aarch64 (10x)
- memmem() now uses KMP on pathological cases
- Disable shared_ptr::owner_before until fixed
- Make iswlower(), iswupper() consistent with glibc
- Remove figure space from iswspace() implementation
- Include line and paragraph separator in iswcntrl()
- Use Musl wcwidth(), iswalpha(), iswpunct(), towlower(), towupper()

third_party/musl/bsearch.c

@@ -0,0 +1,20 @@
+#include <stdlib.h>
+
+void *bsearch(const void *key, const void *base, size_t nel, size_t width, int (*cmp)(const void *, const void *))
+{
+	void *try;
+	int sign;
+	while (nel > 0) {
+		try = (char *)base + width*(nel/2);
+		sign = cmp(key, try);
+		if (sign < 0) {
+			nel /= 2;
+		} else if (sign > 0) {
+			base = (char *)try + width;
+			nel -= nel/2+1;
+		} else {
+			return try;
+		}
+	}
+	return NULL;
+}