update libxev to workaround the io_uring regression in Linux 6.15.4 (#7731)

Fixes #7724

Background at the end of the commit message. The fix in libxev is
described in the PR and commit we pin to here, but basically we swap
read for poll for eventfd/timerfd. libxev commit:
75a10d0fb3

From Jens Axboe on X:

> This will fix it: https://pastebin.com/n7JSZWpW which makes me
suspicious
> that it's an S_IFREG check somewhere else, as anon inodes are now
listed as
> regular files. Has potentially pretty broad implications...

> I think I can already answer why that breaks things - io_uring checks
if
> this is a regular file, and if it is, it doesn't do short reads. Short
> reads on regular files (or a bdev) will cause application issues, as
> basically nobody expects them.

> Now we have what acts like a char dev, but where io_uring will retry
IO
> because the application asked for more data than what was delivered.
This
> will cause the weird slowdowns as data isn't delivered as soon as it's
> available.

## Backporting to 1.1.3

It's a bit risky, but we can back port the libxev update to 1.1.3 (and
release a 1.1.4) since we don't plan on a 1.2 release for a couple
months. Realistically, we've been running the latest libxev on tip
(before this commit) for awhile and there haven't been issues so I think
it's safe enough.

I think we should let this merge settle for a few days at least before
we do that back port though.

build.zig.zon

@@ -8,8 +8,8 @@
 
         .libxev = .{
             // mitchellh/libxev
-            .url = "https://github.com/mitchellh/libxev/archive/9bc52324d4f0c036a3b244e992680a9fb217bbd3.tar.gz",
-            .hash = "libxev-0.0.0-86vtc5b1EgB7vFmt9Tk7ySteR5AeEHW7xcR6gK9dMUD3",
+            .url = "https://github.com/mitchellh/libxev/archive/75a10d0fb374e8eb84948dcfc68d865e755e59c2.tar.gz",
+            .hash = "libxev-0.0.0-86vtcyMBEwA-UpcjfOICyI2GYG8o6MiRbinS1_8g1_rw",
             .lazy = true,
         },
         .vaxis = .{

build.zig.zon.json

@@ -64,10 +64,10 @@
     "url": "https://deps.files.ghostty.org/libpng-1220aa013f0c83da3fb64ea6d327f9173fa008d10e28bc9349eac3463457723b1c66.tar.gz",
     "hash": "sha256-/syVtGzwXo4/yKQUdQ4LparQDYnp/fF16U/wQcrxoDo="
   },
-  "libxev-0.0.0-86vtc5b1EgB7vFmt9Tk7ySteR5AeEHW7xcR6gK9dMUD3": {
+  "libxev-0.0.0-86vtcyMBEwA-UpcjfOICyI2GYG8o6MiRbinS1_8g1_rw": {
     "name": "libxev",
-    "url": "https://github.com/mitchellh/libxev/archive/9bc52324d4f0c036a3b244e992680a9fb217bbd3.tar.gz",
-    "hash": "sha256-VwFByDoptqiN5UkolFQ7TbRhwMERReD9Er2pjxTCYIU="
+    "url": "https://github.com/mitchellh/libxev/archive/75a10d0fb374e8eb84948dcfc68d865e755e59c2.tar.gz",
+    "hash": "sha256-/CSKSuZZfn0aIQlVZ0O8ch5O4gCajYBTTuoetRdo0n4="
   },
   "N-V-__8AAG3RoQEyRC2Vw7Qoro5SYBf62IHn3HjqtNVY6aWK": {
     "name": "libxml2",

build.zig.zon.nix

@@ -186,11 +186,11 @@ in
       };
     }
     {
-      name = "libxev-0.0.0-86vtc5b1EgB7vFmt9Tk7ySteR5AeEHW7xcR6gK9dMUD3";
+      name = "libxev-0.0.0-86vtcyMBEwA-UpcjfOICyI2GYG8o6MiRbinS1_8g1_rw";
       path = fetchZigArtifact {
         name = "libxev";
-        url = "https://github.com/mitchellh/libxev/archive/9bc52324d4f0c036a3b244e992680a9fb217bbd3.tar.gz";
-        hash = "sha256-VwFByDoptqiN5UkolFQ7TbRhwMERReD9Er2pjxTCYIU=";
+        url = "https://github.com/mitchellh/libxev/archive/75a10d0fb374e8eb84948dcfc68d865e755e59c2.tar.gz";
+        hash = "sha256-/CSKSuZZfn0aIQlVZ0O8ch5O4gCajYBTTuoetRdo0n4=";
       };
     }
     {

build.zig.zon.txt

@@ -28,7 +28,7 @@ https://deps.files.ghostty.org/zlib-1220fed0c74e1019b3ee29edae2051788b080cd96e90
 https://github.com/glfw/glfw/archive/e7ea71be039836da3a98cea55ae5569cb5eb885c.tar.gz
 https://github.com/jcollie/ghostty-gobject/releases/download/0.14.0-2025-03-18-21-1/ghostty-gobject-0.14.0-2025-03-18-21-1.tar.zst
 https://github.com/mbadolato/iTerm2-Color-Schemes/archive/6fa671fdc1daf1fcfa025cb960ffa3e7373a2ed8.tar.gz
-https://github.com/mitchellh/libxev/archive/9bc52324d4f0c036a3b244e992680a9fb217bbd3.tar.gz
+https://github.com/mitchellh/libxev/archive/75a10d0fb374e8eb84948dcfc68d865e755e59c2.tar.gz
 https://github.com/mitchellh/zig-objc/archive/3ab0d37c7d6b933d6ded1b3a35b6b60f05590a98.tar.gz
 https://github.com/natecraddock/zf/archive/7aacbe6d155d64d15937ca95ca6c014905eb531f.tar.gz
 https://github.com/vancluever/z2d/archive/1bf4bc81819385f4b24596445c9a7cf3b3592b08.tar.gz

flatpak/zig-packages.json

@@ -79,9 +79,9 @@
   },
   {
     "type": "archive",
-    "url": "https://github.com/mitchellh/libxev/archive/9bc52324d4f0c036a3b244e992680a9fb217bbd3.tar.gz",
-    "dest": "vendor/p/libxev-0.0.0-86vtc5b1EgB7vFmt9Tk7ySteR5AeEHW7xcR6gK9dMUD3",
-    "sha256": "570141c83a29b6a88de5492894543b4db461c0c11145e0fd12bda98f14c26085"
+    "url": "https://github.com/mitchellh/libxev/archive/75a10d0fb374e8eb84948dcfc68d865e755e59c2.tar.gz",
+    "dest": "vendor/p/libxev-0.0.0-86vtcyMBEwA-UpcjfOICyI2GYG8o6MiRbinS1_8g1_rw",
+    "sha256": "fc248a4ae6597e7d1a2109556743bc721e4ee2009a8d80534eea1eb51768d27e"
   },
   {
     "type": "archive",