patch 8.1.1504: sound test still fails on Travis

Problem:    Sound test still fails on Travis.
Solution:   Add more lines to the install section.
diff --git a/.travis.yml b/.travis.yml
index 3a01234..02a449b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,6 +10,9 @@
   - gcc
 
 env:
+  global:
+      # pretend to play sounds
+      AUDIODEV=null
   - &tiny-nogui
     BUILD=yes TEST=test COVERAGE=no FEATURES=tiny "CONFOPT='--disable-gui'" SHADOWOPT= SRCDIR=./src CHECK_AUTOCONF=no
   - &tiny
@@ -121,6 +124,16 @@
     if [[ "${TRAVIS_OS_NAME}" = "linux" ]] && [[ "${CC}" = "clang" ]]; then
       ln -sf "$(which llvm-cov)" /home/travis/bin/gcov
     fi
+  # Should make sound work (might not all be needed)
+  - |
+    if [[ "${TRAVIS_OS_NAME}" = "linux" ]]; then
+      sudo apt-get update -qq
+      sudo usermod -a -G audio travis
+      sudo apt-get install -y portaudio19-dev
+      sudo apt-get install -y libasound2-dev alsa-utils alsa-oss
+      sudo bash test/prep-dummy-soundcard.sh
+      sudo apt-get install -y lame
+    fi
 
 before_script:
   # Start virtual framebuffer to be able to test the GUI. Does not work on OS X.
@@ -128,8 +141,6 @@
     if [[ "${TRAVIS_OS_NAME}" = "linux" ]]; then
       export DISPLAY=:99.0
       sh -e /etc/init.d/xvfb start && sleep 3
-      # pretend to play sounds
-      export AUDIODEV=null
     fi
 
 script:
diff --git a/src/version.c b/src/version.c
index 4d77a57..82e9e38 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1504,
+/**/
     1503,
 /**/
     1502,