diff --git a/.travis.yml b/.travis.yml
index c9a7d3c0afcb948911c6ab5524d0ae92861cfa20..2dc9f85ce15bbb65ebbaab4bc6fab4867b27ccff 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,6 @@
+sudo: required
 language: cpp
+compiler: gcc
 dist: trusty
 notifications:
   email: false
@@ -11,9 +13,17 @@ before_install:
  - source /opt/qt510/bin/qt510-env.sh
 
 script:
+    - export CC=gcc-5
     - mkdir build
     - cd build 
     - cmake ../
     - make libdap-test
     - ./test/libdap-test
 
+addons:
+  apt:
+    sources:
+    - ubuntu-toolchain-r-test
+    packages:
+    - gcc-5
+
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8f2d12b65480a97db25db68200bf914825a0691b..669013777aba6c7c58aba1a9826fe2d6fb207cbf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,8 +4,7 @@ project(libdap C)
 # fix implicit declaration warnings
 add_definitions ("-D_GNU_SOURCE")
 
-set(CMAKE_C_FLAGS "-Wall -Wextra")
-set(CMAKE_C_FLAGS "-std=c11")
+set(CMAKE_C_FLAGS "-std=c11 -Wall -Wextra")
 
 add_subdirectory(core)
 add_subdirectory(crypto)