Merge b8582e8 into b171791

.travis.yml

@@ -178,7 +178,7 @@ install:
     fi
   - if [ "${TRAVIS_OS_NAME}" == "linux" ]; then
       sudo apt-get update -qq;
-      sudo apt-get install -qq unzip;
+      sudo apt-get install -qq unzip cmake3;
       wget https://github.com/bazelbuild/bazel/releases/download/0.10.1/bazel-0.10.1-installer-linux-x86_64.sh --output-document bazel-installer.sh;
       travis_wait sudo bash bazel-installer.sh;
     fi
@@ -188,6 +188,7 @@ install:
     fi
 
 script:
+  - cmake --version
   - cmake -DCMAKE_C_COMPILER=${C_COMPILER} -DCMAKE_CXX_COMPILER=${COMPILER} -DCMAKE_BUILD_TYPE=${BUILD_TYPE} -DCMAKE_CXX_FLAGS="${EXTRA_FLAGS}" -DBENCHMARK_DOWNLOAD_DEPENDENCIES=ON -DBENCHMARK_BUILD_32_BITS=${BUILD_32_BITS} ${EXTRA_OPTIONS} ..
   - make
   - ctest -C ${BUILD_TYPE} --output-on-failure

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 2.8.12)
+cmake_minimum_required (VERSION 3.4.3)
 
 project (benchmark)
 

README.md

@@ -51,6 +51,9 @@ First make sure you have git and cmake installed (If not please install them)
 sudo apt-get install git cmake
 ```
 
+_See [dependencies.md](dependencies.md) for more details about the supported
+versions of build tools._
+
 Now, let's clone the repository and build it
 
 ```

dependencies.md

@@ -0,0 +1,23 @@
+# Build tool dependency policy
+
+To ensure the broadest compatibility when building the benchmark library, but
+still allow forward progress, we require any build tooling to be available for:
+
+* Debian stable AND
+* The last two Ubuntu LTS releases
+
+Currently, this means the highest build tool versions we can use must be
+available for Ubuntu 16.04 (Xenial), Ubuntu 18.04 (Bionic), and Debian stretch.
+
+However, there are projects that rely on Benchmark that require a slightly older
+version than this
+([LLVM](https://github.com/llvm-mirror/llvm/blob/master/CMakeLists.txt)], so we
+will choose something that allows this compatibility requirement to be met.
+
+_Note, [travis](.travis.yml) runs under Ubuntu 14.04 (Trusty) for linux builds._
+
+## cmake
+The current supported version is cmake 3.4.3 as of 2018-11-14.
+
+_Note, this version is also available for Ubuntu 14.04, the previous Ubuntu LTS
+release, as `cmake3`._