diff --git a/Formula/glib.rb b/Formula/glib.rb
index 3f670bb35550..1dac0786a916 100644
--- a/Formula/glib.rb
+++ b/Formula/glib.rb
@@ -6,7 +6,7 @@ class Glib < Formula
   url "https://download.gnome.org/sources/glib/2.64/glib-2.64.4.tar.xz"
   sha256 "f7e0b325b272281f0462e0f7fff25a833820cac19911ff677251daf6d87bce50"
   license "LGPL-2.1"
-  revision 1
+  revision 2
 
   bottle do
     sha256 "5b4079bc14d3e16b745686b6cc7a3bca8877ac914f4ea11b82cda7e5af21c51c" => :catalina
@@ -42,6 +42,14 @@ class Glib < Formula
     sha256 "9e3de41571edaa4bce03959abf885aad4edd069a622a5b642bf40294d748792e"
   end
 
+  # Enables G_GNUC_FALLTHROUGH on clang.
+  # Necessary for pango to build on recent versions of clang.
+  # Will be in the next release.
+  patch do
+    url "https://gitlab.gnome.org/GNOME/glib/-/commit/5f38ae5ffca3213addc5b279a46d537792d031db.patch"
+    sha256 "12128966a693dd45d2e20286437aea13b1fe554aed0907cbc33131d3b76be890"
+  end
+
   def install
     inreplace %w[gio/gdbusprivate.c gio/xdgmime/xdgmime.c glib/gutils.c],
       "@@HOMEBREW_PREFIX@@", HOMEBREW_PREFIX
diff --git a/Formula/pango.rb b/Formula/pango.rb
index c7ed4393a07b..1a8f88c6e853 100644
--- a/Formula/pango.rb
+++ b/Formula/pango.rb
@@ -1,10 +1,21 @@
 class Pango < Formula
   desc "Framework for layout and rendering of i18n text"
   homepage "https://www.pango.org/"
-  url "https://download.gnome.org/sources/pango/1.44/pango-1.44.7.tar.xz"
-  sha256 "66a5b6cc13db73efed67b8e933584509f8ddb7b10a8a40c3850ca4a985ea1b1f"
   license "GPL-2.0"
 
+  stable do
+    url "https://download.gnome.org/sources/pango/1.44/pango-1.44.7.tar.xz"
+    sha256 "66a5b6cc13db73efed67b8e933584509f8ddb7b10a8a40c3850ca4a985ea1b1f"
+
+    # Adopts an upstream patch to fix compilers that are picky about
+    # fallthrough (e.g., newer clang).
+    # Can be removed on the next release.
+    patch do
+      url "https://gitlab.gnome.org/GNOME/pango/-/commit/0b3cd20be5249c51ec981a66c07a39d54d1d1c9d.patch"
+      sha256 "252378845c5b1b09bf5ae1e06200bba7bf3d4bd679aff2888e95233cf8762a76"
+    end
+  end
+
   bottle do
     sha256 "38a8cab63ed7ea37fc5448b74dae21b7f935d4f4ea9c08b658f3553f20ec8f28" => :catalina
     sha256 "643284e68fcb4699572e7ab327a16ae3eb1c242527a96cb404cd98f14f22a893" => :mojave