[Tests] improve test matrix

.travis.yml

@@ -24,13 +24,15 @@ install:
   - chmod +x /tmp/urchin/package/urchin
   - '[ -z "$WITHOUT_CURL" ] || sudo apt-get remove curl -y'
 script:
-  - export CXX=g++-4.8
-  - export CC=gcc-4.8
-  - export PATH=$(echo $PATH | sed 's/::/:/')
-  - export NVM_DIR="${TRAVIS_BUILD_DIR}"
   - if [ -n "${SHELLCHECK-}" ]; then shellcheck -s bash nvm.sh && shellcheck -s sh nvm.sh && shellcheck -s dash nvm.sh && shellcheck -s ksh nvm.sh && shellcheck -s bash install.sh ; fi
   - if [ -z "${SHELLCHECK-}" ]; then make TEST_SUITE=$TEST_SUITE URCHIN=/tmp/urchin/package/urchin test-$SHELL ; fi
 env:
+  global:
+    - CXX=g++-4.8
+    - CC=gcc-4.8
+    - PATH=$(echo $PATH | sed 's/::/:/')
+    - NVM_DIR="${TRAVIS_BUILD_DIR}"
+  matrix:
     - SHELLCHECK=true
     - SHELL=bash TEST_SUITE=install_script
     - SHELL=sh TEST_SUITE=fast