CMake: move version normalization out of get_git_version()

Mainly, i want `get_git_version()` to return true version,
not something sanitized.

CMakeLists.txt

@@ -105,16 +105,26 @@ get_git_version(GIT_VERSION)
 # If no git version can be determined, use the version
 # from the project() command
 if ("${GIT_VERSION}" STREQUAL "0.0.0")
-  set(VERSION "${benchmark_VERSION}")
+  set(VERSION "v${benchmark_VERSION}")
 else()
   set(VERSION "${GIT_VERSION}")
 endif()
+
+# Normalize version: drop "v" prefix, replace first "-" with ".",
+# drop everything after second "-" (including said "-").
+string(STRIP ${VERSION} VERSION)
+if(VERSION MATCHES v[^-]*-)
+   string(REGEX REPLACE "v([^-]*)-([0-9]+)-.*" "\\1.\\2"  NORMALIZED_VERSION ${VERSION})
+else()
+   string(REGEX REPLACE "v(.*)" "\\1" NORMALIZED_VERSION ${VERSION})
+endif()
+
 # Tell the user what versions we are using
-message(STATUS "Google Benchmark version: ${VERSION}")
+message(STATUS "Google Benchmark version: ${VERSION}, normalized to ${NORMALIZED_VERSION}")
 
 # The version of the libraries
-set(GENERIC_LIB_VERSION ${VERSION})
-string(SUBSTRING ${VERSION} 0 1 GENERIC_LIB_SOVERSION)
+set(GENERIC_LIB_VERSION ${NORMALIZED_VERSION})
+string(SUBSTRING ${NORMALIZED_VERSION} 0 1 GENERIC_LIB_SOVERSION)
 
 # Import our CMake modules
 include(AddCXXCompilerFlag)

cmake/GetGitVersion.cmake

@@ -19,26 +19,14 @@ endif()
 set(__get_git_version INCLUDED)
 
 function(get_git_version var)
+  set(GIT_VERSION "v0.0.0")
+
   if(GIT_EXECUTABLE)
       execute_process(COMMAND ${GIT_EXECUTABLE} describe --tags --match "v[0-9]*.[0-9]*.[0-9]*" --abbrev=8 --dirty
           WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
           RESULT_VARIABLE status
-          OUTPUT_VARIABLE GIT_DESCRIBE_VERSION
+          OUTPUT_VARIABLE GIT_VERSION
           ERROR_QUIET)
-      if(status)
-          set(GIT_DESCRIBE_VERSION "v0.0.0")
-      endif()
-
-      string(STRIP ${GIT_DESCRIBE_VERSION} GIT_DESCRIBE_VERSION)
-      if(GIT_DESCRIBE_VERSION MATCHES v[^-]*-) 
-         string(REGEX REPLACE "v([^-]*)-([0-9]+)-.*" "\\1.\\2"  GIT_VERSION ${GIT_DESCRIBE_VERSION})
-      else()
-         string(REGEX REPLACE "v(.*)" "\\1" GIT_VERSION ${GIT_DESCRIBE_VERSION})
-      endif()
-
-      message(STATUS "git version: ${GIT_DESCRIBE_VERSION} normalized to ${GIT_VERSION}")
-  else()
-      set(GIT_VERSION "0.0.0")
   endif()
 
   set(${var} ${GIT_VERSION} PARENT_SCOPE)