Minor optimisations and bug fixes

Fix bug in mt_mpmc.c, in Linux mutexes are not recursive.
Add arena_trim_string() to the arena API
Removing arena->path, now paths are pushed to arena->metadata
Replacing fe->owner[128] with char *owner; the owner is not pushed as a
string to arena->metadata and trimed with arena_trim_string()
Improving cache locality in arena->metadata, the memory layout is not
fe; fe->path; fe->owner.
Cache aligning all arenas except HasherContext->arena to sizeof(void *).
Pushing elements one by one instead of snprintf() in finalize_file() and
hash_worker().
Getting the full path of current directory instead of "."
Fixing bug in path formating, this allow us to remove normalize_path()
from the hot loop.

file_hasher.c

@@ -32,7 +32,11 @@ int main(int argc, char **argv) {
     buf[strcspn(buf, "\r\n")] = 0;
 
     if (buf[0] == 0) {
-      strcpy(folders[0], ".");
+      if (!platform_get_current_directory(folders[0], sizeof(folders[0]))) {
+        fprintf(stderr, "Failed to get current directory\n");
+        return 1;
+      }
+      normalize_path(folders[0]);
       folder_count = 1;
     } else {
       folder_count = parse_paths(buf, folders, 64);
@@ -71,7 +75,18 @@ int main(int argc, char **argv) {
       .max_nbre_blocks = 1,
   };
 
-  mem_arena *gp_arena = arena_create(&params);
+  arena_params params_caligned = {
+      .reserve_size = GiB(1),
+      .commit_size = MiB(16),
+      .align = ARENA_CACHE_ALIGN,
+      .push_size = 0,
+      .allow_free_list = true,
+      .allow_swapback = false,
+      .growth_policy = ARENA_GROWTH_NORMAL,
+      .commit_policy = ARENA_COMMIT_LAZY,
+      .max_nbre_blocks = 1,
+  };
+  mem_arena *gp_arena = arena_create(&params_caligned);
 
   // -------------------------------
   // Detect hardware
@@ -119,7 +134,7 @@ int main(int argc, char **argv) {
   mpmc_init(&file_queue, MiB(1));
 
   // Starting hash threads
-  WorkerContext workers[num_hash_threads];
+  HasherContext workers[num_hash_threads];
   Thread *hash_threads =
       arena_push(&gp_arena, sizeof(Thread) * num_hash_threads, true);
 
@@ -155,8 +170,7 @@ int main(int argc, char **argv) {
 
   for (uint8_t i = 0; i < num_scan_threads; i++) {
     scanners[i].num_threads = num_scan_threads;
-    scanners[i].path_arena = arena_create(&params);
-    scanners[i].meta_arena = arena_create(&params);
+    scanners[i].meta_arena = arena_create(&params_caligned);
     scanners[i].dir_queue = &dir_queue;
     scanners[i].file_queue = &file_queue;
 
@@ -170,7 +184,7 @@ int main(int argc, char **argv) {
   // Initial folder push
   for (int i = 0; i < folder_count; i++) {
     size_t len = strlen(folders[i]) + 1;
-    char *path = arena_push(&scanners[0].path_arena, len, false);
+    char *path = arena_push(&scanners[0].meta_arena, len, false);
     memcpy(path, folders[i], len);
     mpmc_push_work(&dir_queue, path);
   }