Update legacy OS from 18.04 to 20.04

Since Ubuntu 20.04 supports less i386 functionality than 18.04,
it has been necessary to use a smaller set of compile options,
resulting in less compile coverage.

.github/workflows/build.yml

@@ -65,19 +65,19 @@ jobs:
           - CC: gcc
             feature_set: max
             arch: i386
-            os: ubuntu-18.04
+            os: ubuntu-20.04
             name_extra: for 32-bit arch (legacy OS)
 
           - CC: g++
             feature_set: max
             arch: i386
-            os: ubuntu-18.04
+            os: ubuntu-20.04
             name_extra: for 32-bit arch (legacy OS)
 
           - CC: clang
             feature_set: max
             arch: i386
-            os: ubuntu-18.04
+            os: ubuntu-20.04
             name_extra: for 32-bit arch (legacy OS)
 
     name: ${{ matrix.feature_set }} features with ${{ matrix.CC }} ${{ matrix.name_extra }}
@@ -97,8 +97,8 @@ jobs:
       CONF_FLAGS_amd64_max: "--enable-ipv6 --enable-jpeg --enable-fuse --enable-mp3lame
                   --enable-fdkaac --enable-opus --enable-rfxcodec --enable-painter
                   --enable-pixman --with-imlib2 --with-freetype2"
-      CONF_FLAGS_i386_max: "--enable-ipv6 --enable-jpeg --enable-fuse --enable-mp3lame
+      CONF_FLAGS_i386_max: "--enable-ipv6 --enable-jpeg --enable-mp3lame
-                  --enable-fdkaac --enable-opus --enable-rfxcodec --enable-painter
+                  --enable-opus --enable-rfxcodec --enable-painter
                   --disable-pixman --with-imlib2 --with-freetype2
                   --host=i686-linux"
 

scripts/install_xrdp_build_dependencies_with_apt.sh

@@ -103,6 +103,11 @@ in
         esac
         ;;
     i386)
+        # This list is not as complete as the amd64 list. It currently
+        # supports 32-bit CI building only, rather than being a generic
+        # build support tool.
+        # - Ubuntu 18.04 -> 20.04
+        #       Removed fdk-aac-dev:i386 and libfuse-dev:i386
         PACKAGES="$PACKAGES \
             g++-multilib \
             gcc-multilib \
@@ -112,7 +117,6 @@ in
             libjpeg-dev:i386 \
             libimlib2-dev:i386 \
             libmp3lame-dev:i386 \
-            libfdk-aac-dev:i386 \
             libopus-dev:i386 \
             libpam0g-dev:i386 \
             libssl-dev:i386 \
@@ -120,8 +124,7 @@ in
             libxext-dev:i386 \
             libxfixes-dev:i386 \
             libxrandr-dev:i386 \
-            libxrender-dev:i386 \
+            libxrender-dev:i386"
-            libfuse-dev:i386"
 
         dpkg --add-architecture i386
         dpkg --print-architecture