Travis: test with both gcc and clang

Travis does this in parallel so the build doesn't become
twice as long.

diff --git a/.travis.yml b/.travis.yml
index a205373..0fd9d87 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,3 +1,6 @@
 sudo: false
+compiler:
+  - gcc
+  - clang
 language: c
 script: sh build.sh && ./configure && make distcheck