diff --git a/.travis.yml b/.travis.yml
index 24fd6e268e1..9374041925d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -47,8 +47,12 @@ script:
   - export FCFLAGS='-fsanitize=address -fno-omit-frame-pointer'
   - export DISTCHECK_CONFIGURE_FLAGS='--enable-fortran'
   - ./configure --enable-fortran --enable-developer-docs
-  - make
   - make -j distcheck
+  - make -j distclean
+  - export CFLAGS='-std=c99  -Werror'  
+  - ./configure
+  - make -j distcheck
+  - make -j distclean
   - rm -rf build
   - mkdir build
   - cd build