Update .travis.yml

.travis.yml

@@ -5,7 +5,7 @@ dist: trusty
 language: cpp
 # Compiler selection
 compiler:
-  - gcc
+  - gcc-4.9
 # Build steps
 script:
   - ./scripts/reconfigure_script
@@ -18,7 +18,7 @@ script:
   - ./benchmarks/Benchmark_dwf --threads 1
 matrix:
   include:
-    - compiler: gcc
+    - compiler: gcc-4.9
       addons:
         apt:
           sources:
@@ -28,6 +28,7 @@ matrix:
             - libmpfr-dev
             - libgmp-dev
             - libmpc-dev
+            - binutils-dev
       env: CXX=g++-4.9
       env: CXXFLAGS="-mavx2 -mfma -fopenmp -O3 -std=c++11"
       env: LIBS="-fopenmp -lmpfr -lgmp"