Parallel build for dependencies on Travis

Also, check out the v1.0.0-errata1 tag of libaom.

.travis.yml

@@ -5,7 +5,7 @@ env:
   - RUST_BACKTRACE=1
 addons:
   apt:
-    packages: binutils-dev libcurl4-openssl-dev zlib1g-dev libdw-dev libiberty-dev
+    packages: binutils-dev libcurl4-openssl-dev zlib1g-dev libdw-dev libiberty-dev ninja-build
 before_install:
     - wget -O cmake.sh https://cmake.org/files/v3.13/cmake-3.13.3-Linux-x86_64.sh
     - sudo sh cmake.sh --skip-license --exclude-subdir --prefix=/usr
@@ -16,24 +16,22 @@ before_install:
     - wget https://download.videolan.org/contrib/nasm/nasm-2.14.tar.gz
     - tar -xvf nasm-2.14.tar.gz
     - cd nasm-2.14
-    - ./configure
-    - make
-    - sudo make install
+    - ./configure && make -j2 && sudo make install
     - nasm --version
     - cd ..
     - wget -O kcov.tar.gz https://github.com/SimonKagstrom/kcov/archive/v36.tar.gz
     - tar -xvf kcov.tar.gz
     - cd kcov-36
     - mkdir .build && cd .build
-    - cmake .. && make && sudo make install
+    - cmake -GNinja .. && ninja && sudo ninja install
     - cd ../..
-    - git clone https://aomedia.googlesource.com/aom
+    - git clone --depth 1 -b v1.0.0-errata1 https://aomedia.googlesource.com/aom
     - cd aom
     - rm -rf CMakeCache.txt CMakeFiles
     - mkdir -p .build
     - cd .build
-    - cmake .. -DCMAKE_BUILD_TYPE=Release -DENABLE_TESTS=0 -DENABLE_DOCS=0 -DCONFIG_LOWBITDEPTH=1 -DCMAKE_INSTALL_PREFIX=/usr -DCONFIG_PIC=1
-    - make && sudo make install
+    - cmake -GNinja .. -DCMAKE_BUILD_TYPE=Release -DENABLE_TESTS=0 -DENABLE_DOCS=0 -DCONFIG_LOWBITDEPTH=1 -DCMAKE_INSTALL_PREFIX=/usr -DCONFIG_PIC=1
+    - ninja && sudo ninja install
     - cd ../..
 
 jobs: