Build with -Werror for the simplest case

.travis.yml

@@ -3,7 +3,7 @@ compiler:
   - gcc
 
 script: 
-  - autoconf && autoheader && ./configure $BUNDLEDLIBTOM CFLAGS="-O2 -Wall -Wno-pointer-sign" --prefix=$HOME/inst 
+  - autoconf && autoheader && ./configure $BUNDLEDLIBTOM CFLAGS="-O2 -Wall -Wno-pointer-sign $WEXTRAFLAGS" --prefix=$HOME/inst 
   - test "$NOWRITEV" && sed -i s/HAVE_WRITEV/DONT_HAVE_WRITEV/ config.h || true
   - make install
   - ~/inst/bin/dropbearkey -t rsa -f testrsa
@@ -17,7 +17,7 @@ before_install:
   - sudo apt-get install -qq libz-dev libtomcrypt-dev libtommath-dev
 
 env: 
-  - BUNDLEDLIBTOM=--disable-bundled-libtom
+  - BUNDLEDLIBTOM=--disable-bundled-libtom WEXTRAFLAGS=-Werror
   - BUNDLEDLIBTOM=--enable-bundled-libtom
   - MULTI=1
   - NOWRITEV=1