Add SDK/CRT string routines and headers

SDK/CRT/STRING/mem.c

@@ -0,0 +1,53 @@
+/*++
+
+Copyright (c) 2024, Quinn Stephens.
+Provided under the BSD 3-Clause license.
+
+Module Name:
+
+   mem.c
+
+Abstract:
+
+   Provides memory manipulation routines.
+
+--*/
+
+#include <string.h>
+
+void *
+memset (
+    void *dest,
+    int c,
+    size_t count
+    )
+
+{
+    void *ptr = dest;
+
+    while (count--) {
+        *(char *)dest = (char)c;
+        dest = (char *)dest + 1;
+    }
+
+    return ptr;
+}
+
+void *
+memcpy (
+    void *dest,
+    const void *src,
+    size_t count
+    )
+
+{
+    void *ptr = dest;
+
+    while (count--) {
+        *(char *)dest = *(char *)src;
+        dest = (char *)dest + 1;
+        src = (char *)src + 1;
+    }
+
+    return ptr;
+}