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)

.travis.yml

@@ -1,4 +1,5 @@
 language: c
+dist: trusty
 
 os:
   - osx
@@ -70,11 +71,13 @@ addons:
       - 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

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    780,
 /**/
     779,
 /**/