entangle: Fix build with glib 2.82

https://hydra.nixos.org/build/274565015/nixlog/1

`pcre` is no longer needed as the comment longer applies.

`glib-2.0.pc` now has `libsysprof-capture-4` in `Requires.private` field.
Normally, this does not matter since we patch our `pkg-config` to ignore that
outside of static builds but `entangle` was using `pkgconf`, which is not patched.

Let’s switch to standard `pkg-config`.
This will also allow us to clean some more dependencies.

Unfortunately, this also reveals issue with an underspecified `gio-unix-2.0` dependency so we need to fix that.

pkgs/by-name/en/entangle/0001-build-Add-missing-gio-unix-2.0-dependency.patch

···
+From 7f51ec77e1a35bbfb8ced3b7340818a72d859c0e Mon Sep 17 00:00:00 2001
+From: Jan Tojnar <[e-mail]>
+Date: Mon, 14 Oct 2024 00:57:57 +0200
+Subject: [PATCH] build: Add missing gio-unix-2.0 dependency
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+On Nix, we try to isolate dependencies more than usual and have an alternative interpretation of pkg-config’s `Requires.private` field.
+In this environment, Entangle fails to build because it has implicit dependency on gio-unix:
+
+../src/frontend/entangle-camera-manager.c:28:10: fatal error: gio/gunixoutputstream.h: No such file or directory
+   28 | #include <gio/gunixoutputstream.h>
+      |          ^~~~~~~~~~~~~~~~~~~~~~~~~
+
+Let’s add it explicitly.
+---
+ meson.build              | 1 +
+ src/frontend/meson.build | 1 +
+ 2 files changed, 2 insertions(+)
+
+diff --git a/meson.build b/meson.build
+index 1510962..90873ef 100644
+--- a/meson.build
++++ b/meson.build
+@@ -33,6 +33,7 @@ add_global_arguments('-DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_2_38', language :
+ 
+ glib_dep = dependency('glib-2.0', version: glib_min_version)
+ gio_dep = dependency('gio-2.0', version: glib_min_version)
++gio_unix_dep = dependency('gio-unix-2.0', version: glib_min_version)
+ gthread_dep = dependency('gthread-2.0', version: glib_min_version)
+ gmodule_dep = dependency('gmodule-2.0', version: glib_min_version)
+ gdk_pixbuf_dep = dependency('gdk-pixbuf-2.0', version: gdk_pixbuf_min_version)
+diff --git a/src/frontend/meson.build b/src/frontend/meson.build
+index 1ed9d75..81310c8 100644
+--- a/src/frontend/meson.build
++++ b/src/frontend/meson.build
+@@ -90,6 +90,7 @@ entangle_frontend_sources += entangle_frontend_enum_sources
+ entangle_frontend_deps = [
+   gthread_dep,
+   gmodule_dep,
++  gio_unix_dep,
+   gtk_dep,
+   gst_dep,
+   pango_dep,
+-- 
+2.46.0
+

pkgs/by-name/en/entangle/package.nix

···
   ninja,
   perl,
   python3,
-  pkgconf,
+  pkg-config,
   wrapGAppsHook3,
   at-spi2-core,
   dbus,
···
   libunwind,
   libxkbcommon,
   orc,
-  pcre,
-  pcre2,
   udev,
   util-linux,
   xorg,
   zstd,
-  cmake,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
···
       url = "https://gitlab.com/entangle/entangle/-/commit/54795d275a93e94331a614c8712740fcedbdd4f0.patch";
       sha256 = "iEgqGjKa0xwSdctwvNdEV361l9nx+bz53xn3fuDgtzY=";
     })
+
+    # Fix implicit dependency
+    # https://github.com/NixOS/nixpkgs/issues/36468
+    # https://gitlab.com/entangle/entangle/-/merge_requests/61
+    ./0001-build-Add-missing-gio-unix-2.0-dependency.patch
   ];
 
   nativeBuildInputs = [
···
     ninja
     perl # for pod2man and build scripts
     python3 # for build scripts
-    pkgconf
+    pkg-config
     wrapGAppsHook3
     gobject-introspection
-    cmake
   ];
 
   buildInputs =
···
       libunwind
       libxkbcommon
       orc
-      pcre # required by libselinux before we USE_PCRE2
-      pcre2 # required by glib-2.0
       udev
       util-linux
       zstd