travis: convert to build matrix

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

.travis.yml

@@ -1,54 +1,46 @@
 language: c
 
+os: linux
+
+arch:
+    - amd64
+    - ppc64le
+    - arm64
+
+dist:
+    - trusty
+    - xenial
+    - bionic
+    - focal
+
+compiler:
+    - gcc
+    - clang
+
+env:
+    - TARGET=make
+    - TARGET=automake
+    - TARGET=cmake
+    - TARGET=cmake_ninja
+
+script:
+	- mkdir build
+        - if [ "${TARGET}" = "make" ]; then \
+	      make; \
+	  fi
+        - if [ "${TARGET}" = "automake" ]; then \
+	      ./autogen.sh && ./configure CFLAGS="-Werror -Wno-unused-result" && make distcheck; \
+	  fi
+        - if [ "${TARGET}" = "make" ]; then \
+	      cd build && cmake .. && make; \
+	  fi
+        - if [ "${TARGET}" = "make" ]; then \
+	      cd build && cmake .. -GNinja -DCMAKE_BUILD_TYPE=Debug && ninja; \
+	  fi
+
 matrix:
     include:
-        - env: test="x64 4.8.4 (make)"
-          os: linux
-          dist: trusty
-          compiler: gcc
-          script: make
-
-        - env: test="x64 4.8.4 (autotools)"
-          os: linux
-          dist: trusty
-          compiler: gcc
-          script: ./autogen.sh && ./configure CFLAGS="-Werror -Wno-unused-result" && make distcheck
-
-        - env: test="x64 5.0 (autotools)"
-          os: linux
-          dist: trusty
-          compiler: clang
-          script: ./autogen.sh && ./configure CFLAGS="-Werror -Wno-unused-result" && make distcheck
-
-        - env: test="x64 4.8.4 (CMake gcc)"
-          os: linux
-          dist: trusty
-          compiler: gcc
-          before_script:
-              - mkdir gcc_rel && cd gcc_rel
-              - cmake ..
-          script: make
-
-        - env: test="x64 5.0 (CMake clang)"
-          os: linux
-          dist: trusty
-          compiler: clang
-          before_script:
-              - mkdir clang_rel && cd clang_rel
-              - cmake ..
-          script: make
-
-        - env: test="x64 5.0 (CMake clang - Ninja) Debug"
-          os: linux
-          dist: trusty
-          compiler: clang
-          before_script:
-              - mkdir clang_ninja_dbg && cd clang_ninja_dbg
-              - cmake .. -GNinja -DCMAKE_BUILD_TYPE=Debug
-          script: ninja
-
         - env: test="Android NDK (CMake)"
-          os: linux
           language: android
           android:
               components: