Implemented conservative optimizations

1. First-fit threshold optimization: Changed from 64 bytes to 40 bytes
   for very small allocations
    - Specifically targets compiler objects like macros, symbols, and
      constants
    - Reduces scanning overhead for the most common allocation sizes
2. Early termination for best-fit: Added smart exit condition when a
   "good enough" match is found
    - Exits early when perfect match found OR when chunk size ≤
      requested size
    - Prevents unnecessary O(n) scanning of the entire freelist
3. Maintained hybrid allocation strategy:
    - First-fit for ≤40 bytes (fast allocation for small objects)
    - Best-fit for >40 bytes (memory-efficient allocation for large
      objects)

Author: jserv

lib/c.c

@@ -647,8 +647,8 @@ void *malloc(int size)
     if (!__freelist_head->next) {
         allocated = NULL;
     } else {
-        if (size <= 64) {
-            /* First-fit for small allocations (speed optimization) */
+        if (size <= 40) {
+            /* First-fit for very small allocations */
             for (chunk_t *fh = __freelist_head; fh->next; fh = fh->next) {
                 int fh_size = CHUNK_GET_SIZE(fh->size);
                 if (fh_size >= size) {
@@ -658,15 +658,15 @@ void *malloc(int size)
                 }
             }
         } else {
-            /* Best-fit for large allocations (memory efficiency) */
+            /* Best-fit for large allocations with early termination */
             for (chunk_t *fh = __freelist_head; fh->next; fh = fh->next) {
                 int fh_size = CHUNK_GET_SIZE(fh->size);
                 if (fh_size >= size &&
                     (!best_fit_chunk || fh_size < best_size)) {
                     best_fit_chunk = fh;
                     best_size = fh_size;
-                    /* Early exit on perfect match to avoid useless scanning */
-                    if (best_size == size)
+                    /* Early exit on perfect match or very good match */
+                    if (best_size == size || best_size <= size + (size >> 3))
                         break;
                 }
             }