BUILD: Only install packages on Travis if we're actually building

All but one Travis build on the Coverity Scan branch bail before
compilation. We don't need to install packages there then.

.travis.yml

@@ -15,8 +15,16 @@ env:
     # The next declaration is the encrypted COVERITY_SCAN_TOKEN, created
     #   via the "travis encrypt" command using the project repo's public key
     - secure: "dn5Irr/svB2d/iouvSxxoe2SEAWlPUlkNlGWScngWhqSp+kEJ8p3ubQG0ogCK0vGGHPwUYXfIQvHQ8oSc2Z4na8rIwZqvkJnxYYKvPLZpweKhb+xQbpjPwDwEycFDxT+y7mPnRLKRDtdmcuRqMQh8gnxb6TMY9xqlCCvnTfwTmI="
-    - coverity_scan_run_condition='\( "$CC" = gcc \) -a \( $USECMAKE -eq 0 \) -a \( "$TRAVIS_OS_NAME" = linux \)'
-    - coverity_scan_script_test_mode=false
+    - coverity_scan_run_condition='\( "$CC" = "gcc" \) -a \( $USECMAKE -eq 0 \) -a \( "$TRAVIS_OS_NAME" = "linux" \)'
+    - coverity_scan_script_test_mode=true
+    # Various conditions where the Travis CI scripts should behave differently
+    - is_coverity_branch='\( "$TRAVIS_BRANCH" = "coverity_scan" \)'
+    - is_valid_config='\( ! '"$is_coverity_branch"' \) -o \( '"$coverity_scan_run_condition"' \)'
+    - is_valid_osx='\( "$TRAVIS_OS_NAME" = "osx" \) -a \( '"$is_valid_config"' \)'
+    - is_valid_linux='\( "$TRAVIS_OS_NAME" = "linux" \) -a \( '"$is_valid_config"' \)'
+    - is_notcoverity_autot='\( ! '"$is_coverity_branch"' \) -a \( $USECMAKE -eq 0 \)'
+    - is_notcoverity_cmake='\( ! '"$is_coverity_branch"' \) -a \( $USECMAKE -eq 1 \)'
+
   matrix:
     # Let's test both our autoconf and CMake build system
     - USECMAKE=0
@@ -35,8 +43,17 @@ matrix:
 
 # If building on osx, use brew to install dependencies
 before_install:
-  - if [ $TRAVIS_OS_NAME = osx ]; then brew install qt openal-soft mad faad2 libvorbis zlib xz libxml2; fi
-  - if [ $TRAVIS_OS_NAME = osx ]; then brew link --force qt; fi
+  - echo "$is_valid_config"
+  - echo "$is_coverity_branch"
+  - echo "$TRAVIS_BRANCH"
+  - if eval [ $is_coverity_branch ]; then echo "Yup1"; else echo "Nope1"; fi
+  - if eval [ $is_valid_config ]; then echo "Yup2"; else echo "Nope2"; fi
+  - if eval [ $is_valid_osx ]; then echo "Yup3"; else echo "Nope3"; fi
+  - if eval [ $is_valid_linux ]; then echo "Yup4"; else echo "Nope4"; fi
+  - if eval [ $is_notcoverity_autot ]; then echo "Yup5"; else echo "Nope5"; fi
+  - if eval [ $is_notcoverity_cmake ]; then echo "Yup6"; else echo "Nope6"; fi
+  - if eval [ $is_valid_osx ]; then brew install qt openal-soft mad faad2 libvorbis zlib xz libxml2; fi
+  - if eval [ $is_valid_osx ]; then brew link --force qt; fi
 
 # Install a new gcc and our library dependencies.
 # This is a bit of a complicated setup, because:
@@ -50,26 +67,44 @@ before_install:
 # 2) We add the Artful repos, and upgrade the libc, gcc and binutils
 # 3) We install our library dependencies
 before_script:
-  - if [ $TRAVIS_OS_NAME = linux ]; then echo "yes" | sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu xenial main universe restricted multiverse"; fi
-  - if [ $TRAVIS_OS_NAME = linux ]; then sudo apt-get update -qq; fi
-  - if [ $TRAVIS_OS_NAME = linux ]; then sudo apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confnew" -o APT::Force-LoopBreak=1 install dpkg; fi
-  - if [ $TRAVIS_OS_NAME = linux ]; then echo "yes" | sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu artful main universe restricted multiverse"; fi
-  - if [ $TRAVIS_OS_NAME = linux ]; then sudo apt-get update -qq; fi
-  - if [ $TRAVIS_OS_NAME = linux ]; then sudo apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confnew" -o APT::Force-LoopBreak=1 install dpkg gcc g++ libc6-dev libc6 binutils binutils-dev; fi
-  - if [ $TRAVIS_OS_NAME = linux ]; then sudo apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confnew" -o APT::Force-LoopBreak=1 install libboost-all-dev libopenal-dev libmad0-dev libvorbis-dev zlib1g-dev liblzma-dev qtbase5-dev libqt5gui5 libqt5multimedia5 qtmultimedia5-dev libqt5multimediawidgets5; fi
+  - echo "$is_valid_config"
+  - echo "$is_coverity_branch"
+  - echo "$TRAVIS_BRANCH"
+  - if eval [ $is_coverity_branch ]; then echo "Yup1"; else echo "Nope1"; fi
+  - if eval [ $is_valid_config ]; then echo "Yup2"; else echo "Nope2"; fi
+  - if eval [ $is_valid_osx ]; then echo "Yup3"; else echo "Nope3"; fi
+  - if eval [ $is_valid_linux ]; then echo "Yup4"; else echo "Nope4"; fi
+  - if eval [ $is_notcoverity_autot ]; then echo "Yup5"; else echo "Nope5"; fi
+  - if eval [ $is_notcoverity_cmake ]; then echo "Yup6"; else echo "Nope6"; fi
+  - if eval [ $is_valid_linux ]; then echo "yes" | sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu xenial main universe restricted multiverse"; fi
+  - if eval [ $is_valid_linux ]; then sudo apt-get update -qq; fi
+  - if eval [ $is_valid_linux ]; then sudo apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confnew" -o APT::Force-LoopBreak=1 install dpkg; fi
+  - if eval [ $is_valid_linux ]; then echo "yes" | sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu artful main universe restricted multiverse"; fi
+  - if eval [ $is_valid_linux ]; then sudo apt-get update -qq; fi
+  - if eval [ $is_valid_linux ]; then sudo apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confnew" -o APT::Force-LoopBreak=1 install dpkg gcc g++ libc6-dev libc6 binutils binutils-dev; fi
+  - if eval [ $is_valid_linux ]; then sudo apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confnew" -o APT::Force-LoopBreak=1 install libboost-all-dev libopenal-dev libmad0-dev libvorbis-dev zlib1g-dev liblzma-dev qtbase5-dev libqt5gui5 libqt5multimedia5 qtmultimedia5-dev libqt5multimediawidgets5; fi
 
 script:
+  - echo "$is_valid_config"
+  - echo "$is_coverity_branch"
+  - echo "$TRAVIS_BRANCH"
+  - if eval [ $is_coverity_branch ]; then echo "Yup1"; else echo "Nope1"; fi
+  - if eval [ $is_valid_config ]; then echo "Yup2"; else echo "Nope2"; fi
+  - if eval [ $is_valid_osx ]; then echo "Yup3"; else echo "Nope3"; fi
+  - if eval [ $is_valid_linux ]; then echo "Yup4"; else echo "Nope4"; fi
+  - if eval [ $is_notcoverity_autot ]; then echo "Yup5"; else echo "Nope5"; fi
+  - if eval [ $is_notcoverity_cmake ]; then echo "Yup6"; else echo "Nope6"; fi
   # Configure, autotools
-  - if [ \( "$COVERITY_SCAN_BRANCH" != 1 \) -a \( $USECMAKE -eq 0 \) ]; then ./autogen.sh; fi
-  - if [ \( "$COVERITY_SCAN_BRANCH" != 1 \) -a \( $USECMAKE -eq 0 \) ]; then ./configure || cat config.log; fi
+  - if eval [ $is_notcoverity_autot ]; then ./autogen.sh; fi
+  - if eval [ $is_notcoverity_autot ]; then ./configure || cat config.log; fi
   # Configure, CMake
-  - if [ \( "$COVERITY_SCAN_BRANCH" != 1 \) -a \( $USECMAKE -eq 1 \) ]; then cmake .; fi
+  - if eval [ $is_notcoverity_cmake ]; then cmake .; fi
   # Compile
-  - if [ "$COVERITY_SCAN_BRANCH" != 1 ]; then make -j4; fi
+  - if eval [ \! $is_coverity_branch ]; then make -j4; fi
   # Unit tests, autotools
-  - if [ \( "$COVERITY_SCAN_BRANCH" != 1 \) -a \( $USECMAKE -eq 0 \) ]; then echo "" > test-suite.log; make -j4 check || cat test-suite.log; fi
+  - if eval [ $is_notcoverity_autot ]; then echo "" > test-suite.log; make -j4 check || cat test-suite.log; fi
   # Unit tests, CMake
-  - if [ \( "$COVERITY_SCAN_BRANCH" != 1 \) -a \( $USECMAKE -eq 1 \) ]; then make -j4 check; fi
+  - if eval [ $is_notcoverity_cmake ]; then make -j4 check; fi
 
 addons:
   coverity_scan: