travis-ci: add build matrix

.travis.yml

@@ -1,8 +1,5 @@
 language: c
 
-compiler:
-  - gcc
-
 dist: trusty
 
 script: ./travis-ci.sh
@@ -20,3 +17,9 @@ env:
     - ENABLE_GCC_WERROR="--enable-gcc-Werror"
     - SLEEP_A_BIT="sleep 0.1"
     - VERBOSE="1"
+
+matrix:
+  include:
+    - env: TARGET=x86_64
+    - env: TARGET=x32
+    - env: TARGET=x86

travis-ci.sh

@@ -4,6 +4,16 @@ j=-j`getconf _NPROCESSORS_ONLN 2> /dev/null` || j=
 set -x
 git fetch --unshallow
 ./git-set-file-times
+case "${TARGET-}" in
+  x32)
+    CC="$CC -mx32"
+    ;;
+  x86)
+    export DISTCHECK_CONFIGURE_FLAGS='--build=i686-pc-linux-gnu'
+    CC="$CC -m32"
+    ;;
+esac
+export CC_FOR_BUILD="$CC"
 ./bootstrap
-./configure --enable-maintainer-mode ${ENABLE_GCC_WERROR-}
-make $j distcheck VERBOSE=${VERBOSE-}
+./configure --enable-maintainer-mode ${ENABLE_GCC_WERROR-} ${DISTCHECK_CONFIGURE_FLAGS-}
+make -k $j distcheck VERBOSE=${VERBOSE-}