Install gpgsm in .travis.yml for building gpgme.

jsm28 · jsm28 · commit 8d043cea0d17 · 2018-08-14T23:58:03.000Z
diff --git a/.travis.yml b/.travis.yml
@@ -19,6 +19,8 @@ addons:
       - libxapian-dev
       # Required to install gpg
       - swig
+      # Required to build gpgme.
+      - gpgsm
 
 before_install:
   # Sphinx required to build the xapian python bindings
