patch 8.0.0780: build failure on Travis

Problem:    Build failure on Travis.
Solution:   Set distribution explicitly. Use Lua and Ruby dev. (Ken Takata,
            closes #1884)
diff --git a/.travis.yml b/.travis.yml
index a0b8d21..333f6b4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,5 @@
 language: c
+dist: trusty
 
 os:
   - osx
@@ -70,11 +71,13 @@
       - libperl-dev
       - python-dev
       - python3-dev
-      - liblua5.1-0-dev
-      - lua5.1
+      - liblua5.2-dev
+      - lua5.2
+      - ruby-dev
       - cscope
 
 before_install:
+  - rvm reset
   - if [ "$COVERAGE" = "yes" ]; then pip install --user cpp-coveralls; fi
     # needed for https support for coveralls
     # building cffi only works with gcc, not with clang
diff --git a/src/version.c b/src/version.c
index 1654ee3..ddac62f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    780,
+/**/
     779,
 /**/
     778,