libc: Add rand() + srand()

Very basic random number generator, but that's what rand() is.
If you want secure numbers then use arc4random() or something idk

libc/include/stdlib.h

@@ -29,6 +29,8 @@ typedef struct
 
 #define MB_CUR_MAX 4
 
+#define RAND_MAX 32767
+
 #ifdef __cplusplus
 extern "C"
 {
@@ -91,8 +93,11 @@ extern "C"
      * endptr if nonnull. */
     unsigned long strtoul(const char* str, char** endptr, int base);
 
+    /* Return the next pseudorandom number. */
     int rand();
-    void srand(int);
+
+    /* Set the pseudorandom number generator's seed, which will determine the sequence of numbers returned by rand(). */
+    void srand(unsigned int seed);
 
     /* Exit the program normally, performing any registered cleanup actions. */
     __noreturn void exit(int status);

libc/src/stdlib.cpp

@@ -205,4 +205,17 @@ extern "C"
     {
         c_quicksort(base, nmemb, size, compar);
     }
+
+    static unsigned next = 42;
+
+    int rand()
+    {
+        next = next * 1103515245 + 12345;
+        return (int)((unsigned)(next / 65536) % 32768);
+    }
+
+    void srand(unsigned int seed)
+    {
+        next = seed;
+    }
 }