Merge pull request #148 from DiracResearch/cmake-git-fix

AUTHORS

@@ -24,3 +24,4 @@ Oleksandr Sochka <sasha.sochka@gmail.com>
 Paul Redmond <paul.redmond@gmail.com>
 Shuo Chen <chenshuo@chenshuo.com>
 Yusuke Suzuki <utatane.tea@gmail.com>
+Dirac Research 

CONTRIBUTORS

@@ -40,3 +40,4 @@ Paul Redmond <paul.redmond@gmail.com>
 Pierre Phaneuf <pphaneuf@google.com>
 Shuo Chen <chenshuo@chenshuo.com>
 Yusuke Suzuki <utatane.tea@gmail.com>
+Tobias Ulvgård <tobias.ulvgard@dirac.se>

cmake/GetGitVersion.cmake

@@ -10,7 +10,8 @@
 # include(GetGitVersion)
 # get_git_version(GIT_VERSION)
 #
-# Requires CMake 2.6+
+# Requires CMake 2.8.11+
+find_package(Git)
 
 if(__get_git_version)
   return()
@@ -18,17 +19,22 @@ endif()
 set(__get_git_version INCLUDED)
 
 function(get_git_version var)
-  execute_process(COMMAND git describe --match "v[0-9]*.[0-9]*.[0-9]*" --abbrev=8
-      RESULT_VARIABLE status
-      OUTPUT_VARIABLE GIT_VERSION
-      ERROR_QUIET)
-  if(${status})
-      set(GIT_VERSION "v0.0.0")
+  if(GIT_EXECUTABLE)
+      execute_process(COMMAND git describe --match "v[0-9]*.[0-9]*.[0-9]*" --abbrev=8
+          RESULT_VARIABLE status
+          OUTPUT_VARIABLE GIT_VERSION
+          ERROR_QUIET)
+      if(${status})
+          set(GIT_VERSION "v0.0.0")
+      else()
+          string(STRIP ${GIT_VERSION} GIT_VERSION)
+          string(REGEX REPLACE "-[0-9]+-g" "-" GIT_VERSION ${GIT_VERSION})
+      endif()
   else()
-      string(STRIP ${GIT_VERSION} GIT_VERSION)
-      string(REGEX REPLACE "-[0-9]+-g" "-" GIT_VERSION ${GIT_VERSION})
+      set(GIT_VERSION "v0.0.0")
   endif()
 
+
   # Work out if the repository is dirty
   execute_process(COMMAND git update-index -q --refresh
       OUTPUT_QUIET