gtk{2,3,4}: move to pkgs/by-name

this shouldn't create any rebuilds

I unfortunately had to duplicate the setup hooks, however i think it
is ok because they don't change a lot.

pkgs/by-name/gt/gtk3/hooks/clean-immodules-cache.sh

@@ -0,0 +1,15 @@
+# shellcheck shell=bash
+
+fixupOutputHooks+=(_gtkCleanImmodulesCache)
+
+# Clean comments that link to generator of the file
+_gtkCleanImmodulesCache() {
+    # gtk_module_path is where the modules are installed
+    # https://gitlab.gnome.org/GNOME/gtk/-/blob/3.24.24/gtk/gtkmodules.c#L68
+    # gtk_binary_version can be retrived with:
+    # pkg-config --variable=gtk_binary_version gtk+-3.0
+    local f="${prefix:?}/lib/@gtk_module_path@/@gtk_binary_version@/immodules.cache"
+    if [ -f "$f" ]; then
+        sed 's|Created by .*bin/gtk-query-|Created by bin/gtk-query-|' -i "$f"
+    fi
+}

pkgs/by-name/gt/gtk3/hooks/drop-icon-theme-cache.sh

@@ -0,0 +1,19 @@
+# shellcheck shell=bash
+
+# Packages often run gtk-update-icon-cache to include their icons in themes’ icon cache.
+# However, since each package is installed to its own prefix, the files will only collide.
+dropIconThemeCache() {
+    if [[ -z "${dontDropIconThemeCache:-}" ]]; then
+        local icondir="${out:?}/share/icons"
+        if [[ -d "${icondir}" ]]; then
+            # App icons are supposed to go to hicolor theme, since it is a fallback theme as per [icon-theme-spec], but some might still choose to install stylized icons to other themes.
+            find "${icondir}" -name 'icon-theme.cache' -print0 \
+              | while IFS= read -r -d '' file; do
+                echo "Removing ${file}"
+                rm -f "${file}"
+            done
+        fi
+    fi
+}
+
+appendToVar preFixupPhases dropIconThemeCache

pkgs/by-name/gt/gtk4/hooks/clean-immodules-cache.sh

@@ -0,0 +1,15 @@
+# shellcheck shell=bash
+
+fixupOutputHooks+=(_gtkCleanImmodulesCache)
+
+# Clean comments that link to generator of the file
+_gtkCleanImmodulesCache() {
+    # gtk_module_path is where the modules are installed
+    # https://gitlab.gnome.org/GNOME/gtk/-/blob/3.24.24/gtk/gtkmodules.c#L68
+    # gtk_binary_version can be retrived with:
+    # pkg-config --variable=gtk_binary_version gtk+-3.0
+    local f="${prefix:?}/lib/@gtk_module_path@/@gtk_binary_version@/immodules.cache"
+    if [ -f "$f" ]; then
+        sed 's|Created by .*bin/gtk-query-|Created by bin/gtk-query-|' -i "$f"
+    fi
+}

pkgs/by-name/gt/gtk4/hooks/drop-icon-theme-cache.sh

@@ -0,0 +1,19 @@
+# shellcheck shell=bash
+
+# Packages often run gtk-update-icon-cache to include their icons in themes’ icon cache.
+# However, since each package is installed to its own prefix, the files will only collide.
+dropIconThemeCache() {
+    if [[ -z "${dontDropIconThemeCache:-}" ]]; then
+        local icondir="${out:?}/share/icons"
+        if [[ -d "${icondir}" ]]; then
+            # App icons are supposed to go to hicolor theme, since it is a fallback theme as per [icon-theme-spec], but some might still choose to install stylized icons to other themes.
+            find "${icondir}" -name 'icon-theme.cache' -print0 \
+              | while IFS= read -r -d '' file; do
+                echo "Removing ${file}"
+                rm -f "${file}"
+            done
+        fi
+    fi
+}
+
+appendToVar preFixupPhases dropIconThemeCache

pkgs/top-level/all-packages.nix

@@ -6983,8 +6983,6 @@ with pkgs;
 
   pangomm_2_42 = callPackage ../development/libraries/pangomm/2.42.nix { };
 
-  gtk2 = callPackage ../development/libraries/gtk/2.x.nix { };
-
   gtk2-x11 = gtk2.override {
     cairo = cairo.override { x11Support = true; };
     pango = pango.override {
@@ -6994,10 +6992,6 @@ with pkgs;
     gdktarget = "x11";
   };
 
-  gtk3 = callPackage ../development/libraries/gtk/3.x.nix { };
-
-  gtk4 = callPackage ../development/libraries/gtk/4.x.nix { };
-
   # On darwin gtk uses cocoa by default instead of x11.
   gtk3-x11 = gtk3.override {
     cairo = cairo.override { x11Support = true; };