enable Travis to do -m32

This requires changing the compiler that runs the tests from clang to gcc-5.

Author: Daniel Kroening

.travis.yml

@@ -83,6 +83,7 @@ jobs:
             - g++-5
             - libubsan0
             - parallel
+            - libc6-dev-i386
       before_install:
         - mkdir bin ; ln -s /usr/bin/gcc-5 bin/gcc
       # env: COMPILER=g++-5 SAN_FLAGS="-fsanitize=undefined -fno-sanitize-recover -fno-omit-frame-pointer"
@@ -115,6 +116,7 @@ jobs:
             - libwww-perl
             - g++-5
             - libubsan0
+            - libc6-dev-i386
       before_install:
         - mkdir bin ; ln -s /usr/bin/gcc-5 bin/gcc
       # env: COMPILER=g++-5 SAN_FLAGS="-fsanitize=undefined -fno-sanitize-recover -fno-omit-frame-pointer"
@@ -140,8 +142,9 @@ jobs:
             - libstdc++-5-dev
             - libubsan0
             - parallel
+            - libc6-dev-i386
       before_install:
-        - mkdir bin ; ln -s /usr/bin/clang-3.7 bin/gcc
+        - mkdir bin ; ln -s /usr/bin/gcc-5 bin/gcc
         - export CCACHE_CPP2=yes
       # env: COMPILER=clang++-3.7 SAN_FLAGS="-fsanitize=undefined -fno-sanitize-recover=undefined,integer -fno-omit-frame-pointer"
       env:
@@ -165,8 +168,9 @@ jobs:
             - clang-3.7
             - libstdc++-5-dev
             - libubsan0
+            - libc6-dev-i386
       before_install:
-        - mkdir bin ; ln -s /usr/bin/clang-3.7 bin/gcc
+        - mkdir bin ; ln -s /usr/bin/gcc-5 bin/gcc
         - export CCACHE_CPP2=yes
       # env: COMPILER=clang++-3.7 SAN_FLAGS="-fsanitize=undefined -fno-sanitize-recover=undefined,integer -fno-omit-frame-pointer"
       env:
@@ -188,6 +192,7 @@ jobs:
             - ubuntu-toolchain-r-test
           packages:
             - g++-5
+            - libc6-dev-i386
       before_install:
         - mkdir bin ; ln -s /usr/bin/gcc-5 bin/gcc
       install: