Use the git-version CMake module.

Use the newly added CMake module that determines the git hash of the
source repository.  Additionally, for the CMake-based build system,
(1) reproduce the logic from file `git-hash.sh' for determining the
appropriate git hash to build into C-Reduce; and (2) actually pass the
git hash to the C/C++ compilers.

This includes the ability to "burn the hash" into a release tarball.

Author: eeide

.gitattributes

@@ -1,3 +1,4 @@
-*		text=auto
-git-hash.sh	export-subst
-tests/test0.bat     -text
+*			text=auto
+CMakeLists.txt		export-subst
+git-hash.sh		export-subst
+tests/test0.bat		-text

CMakeLists.txt

@@ -11,11 +11,38 @@
 cmake_minimum_required(VERSION 2.8.12)
 project(creduce)
 
+list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")
+
 include(CheckIncludeFile)
 include(CheckCXXCompilerFlag)
+include(GetGitRevisionDescription)
 
 ###############################################################################
 
+# Determine the short git hash for the source tree.  The logic here follows the
+# logic in the `git-hash.sh` script.
+#
+## METHOD 1: The source tree is the result of `git archive'.
+# `git archive' inserts the abbreviated hash of the archive's commit into this
+# file.  (See the `.gitattributes' file.)
+#
+set(GIT_HASH "$Format:%h$")
+if(GIT_HASH MATCHES "^\\$")
+  ## METHOD 2: The source tree is a git repository.
+  get_git_head_revision(GIT_REFSPEC GIT_HASH)
+  if(NOT GIT_HASH STREQUAL "GITDIR-NOTFOUND")
+    # Trim to the short hash.
+    string(SUBSTRING "${GIT_HASH}" 0 7 GIT_HASH)
+  else()
+    ## METHOD 3: Give up.
+    set(GIT_HASH "unknown")
+  endif()
+endif()
+
+add_definitions("-DGIT_VERSION=\"${GIT_HASH}\"")
+
+###
+
 # Generate config.h
 #
 set(ENABLE_TRANS_ASSERT ON CACHE BOOL "Use assert() in clang_delta transformations.")
@@ -47,11 +74,6 @@ configure_file("cmake_config.h.in" "${PROJECT_BINARY_DIR}/config.h")
 
 ###
 
-execute_process(COMMAND "git" "show" "-s" "--format=%h" WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}" OUTPUT_VARIABLE creduce_GIT_HASH)
-string(STRIP "${creduce_GIT_HASH}" creduce_GIT_HASH)
-
-###
-
 # Include this flag if the C++ compiler supports it.
 # See LLVM file `share/llvm/cmake/HandleLLVMOptions.cmake`.
 check_cxx_compiler_flag(

creduce/CMakeLists.txt

@@ -221,10 +221,10 @@ string(REPLACE "@PACKAGE_VERSION@" "${creduce_PACKAGE_VERSION}"
   CREDUCE_CONTENT "${CREDUCE_CONTENT}")
 string(REPLACE "@VERSION@" "${creduce_VERSION}"
   CREDUCE_CONTENT "${CREDUCE_CONTENT}")
-string(REPLACE "@GIT_HASH@" "${creduce_GIT_HASH}"
-  CREDUCE_CONTENT "${CREDUCE_CONTENT}")
 # ENE: I do not understand why the \'s seem to be required in the following
 # match strings.
+string(REPLACE "\@GIT_HASH@" "${GIT_HASH}"
+  CREDUCE_CONTENT "${CREDUCE_CONTENT}")
 string(REPLACE "\@ASTYLE@" "${ASTYLE}"
   CREDUCE_CONTENT "${CREDUCE_CONTENT}")
 string(REPLACE "\@CLANG_FORMAT@" "${CLANG_FORMAT}"