Remove libthai from the excludelist and improve excludelist formatting (

#555)

* Removed libthai from the excludelist and improved excludelist formatting

libthai.so.0 has been removed from the excludelist.
The original reason why libthai had been added to it is an issue that occurs when libpango is not bundled but libthai is (see #538). But since then, libpango had been removed from the excludelist in 2022. This means that the original reason why libthai had been excluded is no longer relevant. Therefore it could be removed from the excludelist. This fixes #538.

Additionally, the excludelist formatting has been improved. There had been different places scattered across the excludelist in which libraries had been excluded or not excluded due to other libraries (like libthai / libpango). They have all been brought together (with all information and reasoning) in one block to prevent issues like this in the future.
Additionally, missing information out of #528 has been added to this block.

* uses: actions/checkout@v4, since v2 does not work anymore

* Need image: ubuntu:20.04 so that checkout can work?

---------

Co-authored-by: probonopd <probonopd@users.noreply.github.com>

.github/workflows/build.yml

@@ -15,11 +15,11 @@ jobs:
   build:
     runs-on: ubuntu-20.04
     container:
-      image: ubuntu:18.04
+      image: ubuntu:20.04
       options: --privileged
     steps:
     - name: Checkout code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Install dependencies
       run: |

excludelist

@@ -87,22 +87,39 @@ libX11-xcb.so.1
 # https://github.com/probonopd/linuxdeployqt/issues/582
 # Uncertain if this is required to be bundled for some distributions - if so, please let us know
 
-# The following libraries need to be privately bundled
-# Workaround for: /lib/x86_64-linux-gnu/libgio-2.0.so.0: undefined symbol: g_module_open_full
-# https://github.com/AppImage/pkg2appimage/pull/500#issuecomment-997183221
-# Workaround for: <AppDir>/usr/lib/x86_64-linux-gnu/libgnutls.so.30: version `GNUTLS_3_6_9' not found (required by /lib64/libglib-2.0.so.0)
-# https://github.com/probonopd/Emacs.AppImage/issues/16
-# NOTE: Privately bundling libglib-2.0.so.0 and libgobject-2.0.so.0 may break https://wiki.gnome.org/Projects/Libsecret,
-# see https://github.com/probonopd/linuxdeployqt/issues/544 for details
+# --- Bundling GLib and its consequences ---
+# The following libraries need to be privately bundled, otherwise this error can happen:
+# - <AppDir>/usr/lib/x86_64-linux-gnu/libgnutls.so.30: version `GNUTLS_3_6_9' not found (required by /lib64/libglib-2.0.so.0)
+# See https://github.com/probonopd/Emacs.AppImage/issues/16
+# - /lib/x86_64-linux-gnu/libgio-2.0.so.0: undefined symbol: g_module_open_full
+# See https://github.com/AppImage/pkg2appimage/pull/500#issuecomment-997183221
 # libgio-2.0.so.0
 # libglib-2.0.so.0
 # libgmodule-2.0.so.0
 # libgobject-2.0.so.0
 # libgthread-2.0.so.0
+# NOTE: Privately bundling libglib-2.0.so.0 and libgobject-2.0.so.0 may break https://wiki.gnome.org/Projects/Libsecret,
+# see https://github.com/probonopd/linuxdeployqt/issues/544 for details
+# NOTE: Privately bundling libgio-2.0.so.0 can lead to this error on Ubuntu:
+# symbol lookup error: /usr/lib/x86_64-linux-gnu/gtk-2.0/modules/liboverlay-scrollbar.so: undefined symbol: g_settings_new
 
-# libgio-2.0.so.0 # Commented out here due to the reason stated in the block above
-# Workaround for:
-# On Ubuntu, "symbol lookup error: /usr/lib/x86_64-linux-gnu/gtk-2.0/modules/liboverlay-scrollbar.so: undefined symbol: g_settings_new"
+# Since we bundle GLib (again), we have to bundle libpango to avoid undefined symbol: g_memdup2 etc.
+# see, e.g., https://github.com/TheAssassin/AppImageLauncher/issues/508
+# libpangoft2-1.0.so.0
+# libpangocairo-1.0.so.0
+# libpango-1.0.so.0
+# NOTE: Pango requires libharfbuzz >= 2.6.0 which isn't available on some older systems, so this error can happen:
+# libpango-1.0.so.0: undefined symbol: hb_ot_layout_get_horizontal_baseline_tag_for_script
+# See https://github.com/AppImageCommunity/pkg2appimage/issues/528
+
+# Commented as we currently bundle libpango
+# If libthai is bundled but libpango is not, this error can happen:
+# audacity: /tmp/.mount_AudaciUsFbON/usr/lib/libthai.so.0: version `LIBTHAI_0.1.25' not found (required by /usr/lib64/libpango-1.0.so.0)
+# on openSUSE Tumbleweed
+# libthai.so.0
+# If libcairo is bundled but libpango is not, this error can happen:
+# Can get symbol lookup error: /lib64/libpango-1.0.so.0: undefined symbol: g_log_structured_standard
+# --- Bundling GLib and its consequences ---
 
 # libgdk-x11-2.0.so.0 # Missing on openSUSE-Tumbleweed-KDE-Live-x86_64-Snapshot20170601-Media.iso
 # libgtk-x11-2.0.so.0 # Missing on openSUSE-Tumbleweed-KDE-Live-x86_64-Snapshot20170601-Media.iso
@@ -120,11 +137,6 @@ libfontconfig.so.1
 # Workaround for:
 # Application stalls when loading fonts during application launch; e.g., KiCad on ubuntu-mate
 
-libthai.so.0
-# Workaround for:
-# audacity: /tmp/.mount_AudaciUsFbON/usr/lib/libthai.so.0: version `LIBTHAI_0.1.25' not found (required by /usr/lib64/libpango-1.0.so.0)
-# on openSUSE Tumbleweed
-
 # other "low-level" font rendering libraries
 # should fix https://github.com/probonopd/linuxdeployqt/issues/261#issuecomment-377522251
 # and https://github.com/probonopd/linuxdeployqt/issues/157#issuecomment-320755694
@@ -174,16 +186,6 @@ libuuid.so.1
 # libwind.so.0 # Missing on openSUSE LEAP 42.0
 libz.so.1
 
-# since we now bundle GLib again, we have to bundle pango as well to avoid undefined symbol: g_memdup2 etc.
-# see, e.g., https://github.com/TheAssassin/AppImageLauncher/issues/508
-#libpangoft2-1.0.so.0
-#libpangocairo-1.0.so.0
-#libpango-1.0.so.0
-
-# FIXME:
-# Can get symbol lookup error: /lib64/libpango-1.0.so.0: undefined symbol: g_log_structured_standard
-# if libcairo is bundled but libpango is not
-
 # Workaround for:
 # e.g., Spotify
 # relocation error: /lib/x86_64-linux-gnu/libgcrypt.so.20: