Split str* and mem* into string.[ch]

armsrc/string.h

@@ -0,0 +1,10 @@
+#ifndef __STRING_H
+#define __STRING_H
+
+int strlen(const char *str);
+void *memcpy(void *dest, const void *src, int len);
+void *memset(void *dest, int c, int len);
+int memcmp(const void *av, const void *bv, int len);
+char *strncat(char *dest, const char *src, unsigned int n);
+
+#endif /* __STRING_H */