nix: build improvements (#5952)

* scripts: allow using existing variable values in generateVersion.sh

* nix: populate versioning variables

* nix: remove unused meson input

* nix: remove unnecessary hyprland-protocols dependency

* Nix: remove nixConfig from flake

It's more annoying than helpful.

* CI/Nix: fix PR build failure

---------

Co-authored-by: Mihai Fufezan <mihai@fufexan.net>

nix/default.nix

@@ -5,7 +5,6 @@
   pkgconf,
   makeWrapper,
   cmake,
-  meson,
   ninja,
   binutils,
   cairo,
@@ -13,7 +12,6 @@
   fribidi,
   git,
   hyprcursor,
-  hyprland-protocols,
   hyprlang,
   hyprwayland-scanner,
   jq,
@@ -72,22 +70,12 @@ assert lib.assertMsg (!hidpiXWayland) "The option `hidpiXWayland` has been remov
     postPatch = ''
       # Fix hardcoded paths to /usr installation
       sed -i "s#/usr#$out#" src/render/OpenGL.cpp
-
-      # Generate version.h
-      cp src/version.h.in src/version.h
-      substituteInPlace src/version.h \
-        --replace-warn "@HASH@" '${commit}' \
-        --replace-warn "@BRANCH@" "" \
-        --replace-warn "@MESSAGE@" "" \
-        --replace-warn "@DATE@" "${date}" \
-        --replace-warn "@TAG@" "" \
-        --replace-warn "@DIRTY@" '${
-        if commit == ""
-        then "dirty"
-        else ""
-      }'
     '';
 
+    DATE = date;
+    HASH = commit;
+    DIRTY = if commit == "" then "dirty" else "";
+
     nativeBuildInputs = lib.concatLists [
       [
         hyprwayland-scanner
@@ -118,7 +106,6 @@ assert lib.assertMsg (!hidpiXWayland) "The option `hidpiXWayland` has been remov
         fribidi
         git
         hyprcursor.dev
-        hyprland-protocols
         hyprlang
         libGL
         libdrm