Generate a C file with git revision string

Former-commit-id: b70cf214ee64d245cbb6b2337b1a4d4e922429c9

CMakeLists.txt

@@ -1,7 +1,11 @@
 cmake_minimum_required(VERSION 3.0.2)
 include(CMakeAddFortranSubdirectory)
+include(version.cmake)
+
 project (QPMS)
 
+set(CMAKE_BUILD_TYPE Debug)
+
 macro(use_c99)
   if (CMAKE_VERSION VERSION_LESS "3.1")
     if (CMAKE_C_COMPILER_ID STREQUAL "GNU")
@@ -24,4 +28,4 @@ cmake_add_fortran_subdirectory (amos
 	LIBRARIES amos
 	NO_EXTERNAL_INSTALL)
 add_subdirectory (qpms)
-
+#add_subdirectory (apps/transop-ewald)

version.cmake

@@ -0,0 +1,34 @@
+# based on https://www.mattkeeter.com/blog/2018-01-06-versioning/
+
+execute_process(COMMAND git describe --tags --dirty --always
+                OUTPUT_VARIABLE GIT_REV
+                ERROR_QUIET)
+
+# Check whether we got any revision (which isn't
+# always the case, e.g. when someone downloaded a zip
+# file from Github instead of a checkout)
+if ("${GIT_REV}" STREQUAL "")
+    set(GIT_REV "N/A")
+    set(GIT_BRANCH "N/A")
+else()
+    execute_process(
+        COMMAND git rev-parse --abbrev-ref HEAD
+        OUTPUT_VARIABLE GIT_BRANCH)
+
+    string(STRIP "${GIT_REV}" GIT_REV)
+    string(STRIP "${GIT_BRANCH}" GIT_BRANCH)
+endif()
+
+set(VERSION "const char* GIT_REV=\"${GIT_REV}\";
+const char* GIT_BRANCH=\"${GIT_BRANCH}\";")
+
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/version.cpp)
+    file(READ ${CMAKE_CURRENT_SOURCE_DIR}/version.cpp VERSION_)
+else()
+    set(VERSION_ "")
+endif()
+
+if (NOT "${VERSION}" STREQUAL "${VERSION_}")
+    file(WRITE ${CMAKE_CURRENT_SOURCE_DIR}/version.cpp "${VERSION}")
+endif()
+