build CHANGE remove unnecessary gcc dependency
diff --git a/.travis.yml b/.travis.yml
index e6312e3..29c8b72 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,14 +10,6 @@
       dist: trusty
       sudo: required
       compiler: gcc
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-7
-      env:
-        - MATRIX_EVAL="CC=gcc-7 && CXX=g++-7"
     - os: osx
       compiler: gcc
   allow_failures:
@@ -36,7 +28,7 @@
   - cd ../..
   - if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew update; fi
   - if [ "$TRAVIS_OS_NAME" = "linux" ]; then sudo apt-get update -qq; sudo apt-get install -y valgrind; fi
-  - if [ "$TRAVIS_OS_NAME" = "linux" -a "$CC" = "gcc-7" ]; then pip install --user codecov; export CFLAGS="-coverage"; fi
+  - if [ "$TRAVIS_OS_NAME" = "linux" -a "$CC" = "gcc" ]; then pip install --user codecov; export CFLAGS="-coverage"; fi
 
 script:
   - mkdir build && cd build
@@ -46,4 +38,4 @@
   - cd -
 
 after_success:
-  - if [ "$TRAVIS_OS_NAME" = "linux" -a "$CC" = "gcc-7" ]; then codecov; fi
+  - if [ "$TRAVIS_OS_NAME" = "linux" -a "$CC" = "gcc" ]; then codecov; fi