reduce the number of builds

a single build of clang and gcc each is enough

.travis.yml

@@ -1,5 +1,38 @@
 language: c
 
+matrix:
+  include:
+    - compiler: clang
+      os: osx
+      env: DO_PUSH_ARTIFACT=yes
+    - compiler: gcc
+      os: linux
+      env:
+        - DO_SIMULATION=yes
+        - ENABLE_DOC=--enable-doc
+      sudo: true
+    - env:
+        - HOST=x86_64-w64-mingw32
+        - DO_PUSH_ARTIFACT=yes
+    - env:
+        - HOST=i686-w64-mingw32
+        - DO_PUSH_ARTIFACT=yes
+    - env: DO_COVERITY_SCAN=yes
+
+env:
+  global:
+    # The next declaration are encrypted envirnmet variables, created via the
+    # "travis encrypt" command using the project repo's public key
+    # COVERITY_SCAN_TOKEN
+    - secure: "UkHn7wy4im8V1nebCWbAetnDSOLRUbOlF6++ovk/7Bnso1/lnhXHelyzgRxfD/oI68wm9nnRV+RQEZ9+72Ug1CyvHxyyxxkwal/tPeHH4B/L+aGdPi0id+5OZSKIm77VP3m5s102sJMJgH7DFd03+nUd0K26p0tk8ad4j1geV4c="
+    # GH_TOKEN
+    - secure: "cUAvpN/XUPMIN5cgWAbIOhghRoLXyw7SCydzGaJ1Ucqb9Ml2v5iuLLuN57YbZHTiWw03vy6rYVzzwMDrHX8r3oUALsv7ViJHG4PzIe7fAFZsZpHECmGsp6SEnue7m7BNy3FT8KYbiXxnxDO0SxmFXlrPAYR0WMZCWx2TENYcafs="
+    - COVERITY_SCAN_BRANCH_PATTERN="(master|coverity.*)"
+    - COVERITY_SCAN_NOTIFICATION_EMAIL="viktor.tarasov@gmail.com"
+    - COVERITY_SCAN_BUILD_COMMAND="make -j 4"
+    - COVERITY_SCAN_PROJECT_NAME="$TRAVIS_REPO_SLUG"
+    - SOURCE_DATE_EPOCH=$(git log -1 --pretty=%ct)
+
 addons:
   apt_packages:
     - binutils-mingw-w64-i686
@@ -17,46 +50,6 @@ addons:
     - pcscd
     - check
 
-env:
-  global:
-    # The next declaration are encrypted envirnmet variables, created via the
-    # "travis encrypt" command using the project repo's public key
-    # COVERITY_SCAN_TOKEN
-    - secure: "UkHn7wy4im8V1nebCWbAetnDSOLRUbOlF6++ovk/7Bnso1/lnhXHelyzgRxfD/oI68wm9nnRV+RQEZ9+72Ug1CyvHxyyxxkwal/tPeHH4B/L+aGdPi0id+5OZSKIm77VP3m5s102sJMJgH7DFd03+nUd0K26p0tk8ad4j1geV4c="
-    # GH_TOKEN
-    - secure: "cUAvpN/XUPMIN5cgWAbIOhghRoLXyw7SCydzGaJ1Ucqb9Ml2v5iuLLuN57YbZHTiWw03vy6rYVzzwMDrHX8r3oUALsv7ViJHG4PzIe7fAFZsZpHECmGsp6SEnue7m7BNy3FT8KYbiXxnxDO0SxmFXlrPAYR0WMZCWx2TENYcafs="
-    - COVERITY_SCAN_BRANCH_PATTERN="(master|coverity.*)"
-    - COVERITY_SCAN_NOTIFICATION_EMAIL="viktor.tarasov@gmail.com"
-    - COVERITY_SCAN_BUILD_COMMAND="make -j 4"
-    - COVERITY_SCAN_PROJECT_NAME="$TRAVIS_REPO_SLUG"
-    - SOURCE_DATE_EPOCH=$(git log -1 --pretty=%ct)
-
-matrix:
-  fast_finish: true
-  include:
-    - compiler: clang
-      os: osx
-      env: DO_PUSH_ARTIFACT=yes
-    - compiler: gcc
-      os: osx
-    - compiler: clang
-      os: linux
-      env: ENABLE_DOC=--enable-doc
-    - compiler: gcc
-      os: linux
-      env: DO_SIMULATION=yes
-      sudo: true
-    - os: linux
-      env:
-        - HOST=x86_64-w64-mingw32
-        - DO_PUSH_ARTIFACT=yes
-    - os: linux
-      env:
-        - HOST=i686-w64-mingw32
-        - DO_PUSH_ARTIFACT=yes
-    - os: linux
-      env: DO_COVERITY_SCAN=yes
-
 before_install:
   - if [ "$TRAVIS_OS_NAME" == "osx" ]; then
         brew update;
@@ -205,6 +198,9 @@ after_script:
       .github/push_artifacts.sh "Travis CI build ${TRAVIS_JOB_NUMBER}";
     fi
 
+before_cache:
+    - brew cleanup
+
 cache:
   apt: true
   ccache: true
@@ -215,6 +211,3 @@ cache:
      - openpace_bin
   files:
      - isetup-5.5.6.exe
-
-before_cache:
-    - brew cleanup