Add memory.h with memcpy and memmove declarations

Define memory management functions and include guards.

Adding a home for memory functions memset, memcpy, memcmp, memmove

This is the header

kernel/memory.h

@@ -0,0 +1,25 @@
+#ifndef MEMORY_H
+#define MEMORY_H
+
+#include <stddef.h>   /* size_t, NULL */
+#include <stdint.h>   /* uint8_t */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* C11 / POSIX-2004 signatures */
+void *memcpy(void *restrict dst, const void *restrict src, size_t n);
+void *memmove(void *dst, const void *src, size_t n);
+/*int   memcmp(const void *s1, const void *s2, size_t n); */
+
+/* Optional fast-path using 32-bit loads (x86 only) */
+#if defined(__i386__) && !defined(MEMORY_NO_OPT)
+# define MEMORY_OPTIMIZED 1
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MEMORY_H */