[travis] Build with introspection enabled

.travis.yml

@@ -15,10 +15,11 @@ install:
   - sudo apt-get install libcairo2-dev # for utils
   - sudo apt-get install libicu-dev # for extra unicode functions
   - sudo apt-get install libgraphite2-dev # for extra shapers
+  - sudo apt-get install libgirepository1.0-dev # for gobject-introspection
   - sudo pip install cpp-coveralls # for coveralls.io code coverage tracking
 script:
   - NOCONFIGURE=1 ./autogen.sh
-  - ./configure --with-freetype --with-glib --with-gobject --with-cairo --with-icu --with-graphite2
+  - ./configure --with-freetype --with-glib --with-gobject --with-cairo --with-icu --with-graphite2 --enable-introspection
   - make && make check && { rm -f src/.libs/NONE.gcov; touch src/NONE; test $CC != gcc || coveralls; }
 notifications:
   irc: "irc.freenode.org#harfbuzz"