Add in NitroSDK headers.

From pokeheartgold.

lib/include/string.h

@@ -0,0 +1,28 @@
+#ifndef MSL_STRING_H_
+#define MSL_STRING_H_
+
+#include <ansi_params.h>
+#include <size_t.h>
+
+_MSL_BEGIN_NAMESPACE_STD
+_MSL_BEGIN_EXTERN_C
+
+void *memset(void *data, int value, size_t size);
+void *memmove(void *dest, const void *src, size_t size);
+void *memcpy(void *dest, const void *src, size_t size);
+void *memchr(const void *arr, int value, size_t size);
+int memcmp(const void *a, const void *b, size_t size);
+char *strcpy(char *dest, const char *src);
+unsigned strlen(const char *str);
+char *strncpy(char *dest, const char *src, size_t n);
+int strcmp(const char *a, const char *b);
+char *strcat(char *dest, const char *src);
+char *strncat(char *dest, const char *src, size_t n);
+unsigned strspn(const char *a, const char *b);
+char *strtok(char *str, const char *sep);
+char *strstr(const char *haystack, const char *needle);
+
+_MSL_END_EXTERN_C
+_MSL_END_NAMESPACE_STD
+
+#endif //MSL_STRING_H_