Kernel/std: Add strdup()

kernel/include/std/string.h

@@ -17,3 +17,5 @@ void* memcpy(void* dest, const void* src, size_t n);
 void* memset(void* dest, int c, size_t n);
 int memcmp(const void* a, const void* b, size_t n);
 void* memmove(void* dest, void* src, size_t n);
+
+char* strdup(const char* src);

kernel/src/std/string.cpp

@@ -1,4 +1,5 @@
-#include <string.h>
+#include "std/string.h"
+#include "std/stdlib.h"
 
 size_t strlen(const char* __s)
 {
@@ -122,3 +123,11 @@ void* memmove(void* dest, void* src, size_t n)
     }
     return dest;
 }
+
+char* strdup(const char* src)
+{
+    size_t length = strlen(src);
+    char* duplicated = (char*)kmalloc(length + 1);
+    memcpy(duplicated, src, length + 1);
+    return duplicated;
+}