Enable caching for CMake builds (hopefully)

Author: reuk

.travis.yml

@@ -153,6 +153,7 @@ jobs:
 
     - stage: Test different OS/CXX/Flags
       os: linux
+      cache: ccache
       env:
         - BUILD_SYSTEM=cmake
       addons:
@@ -162,22 +163,20 @@ jobs:
           packages:
             - g++-5
       install:
-        - mkdir build
-        - cmake -Bbuild -H. '-DCMAKE_BUILD_TYPE=Release' '-DCMAKE_CXX_COMPILER=g++-5'
+        - cmake -H. -Bbuild '-DCMAKE_BUILD_TYPE=Release' '-DCMAKE_CXX_FLAGS_RELEASE=-O3' '-DCMAKE_CXX_FLAGS=-Wall -Wpedantic -Werror' '-DCMAKE_CXX_COMPILER=g++-5'
         - cmake --build build -- -j4
       script: (cd build; ctest -V -L CORE)
-      before_cache:
 
     - stage: Test different OS/CXX/Flags
       os: osx
+      cache: ccache
       env:
         - BUILD_SYSTEM=cmake
+        - CCACHE_CPP2=yes
       install:
-        - mkdir build
-        - cmake -Bbuild -H. '-DCMAKE_BUILD_TYPE=Release' '-DCMAKE_OSX_ARCHITECTURES=i386;x86_64'
+        - cmake -H. -Bbuild '-DCMAKE_BUILD_TYPE=Release' '-DCMAKE_CXX_FLAGS_RELEASE=-O3' '-DCMAKE_CXX_FLAGS=-Wall -Wpedantic -Werror' '-DCMAKE_OSX_ARCHITECTURES=i386;x86_64'
         - cmake --build build -- -j4
       script: (cd build; ctest -V -L CORE)
-      before_cache:
 
 
   allow_failures:

CMakeLists.txt

@@ -1,5 +1,10 @@
 cmake_minimum_required(VERSION 3.2)
 
+find_program(CCACHE_PROGRAM ccache)
+if(CCACHE_PROGRAM)
+    set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE "${CCACHE_PROGRAM}")
+ endif()
+
 set(CMAKE_OSX_DEPLOYMENT_TARGET 10.9)
 
 include(GNUInstallDirs)