Embed git commit hash in the "About" dialog.

Also, remove usage of __DATE__ and __TIME__ to make the build fully
deterministic. They are redundant once we have the commit hash,
anyway.

CMakeLists.txt

@@ -17,9 +17,12 @@ set(CMAKE_USER_MAKE_RULES_OVERRIDE_CXX
 
 # project
 
+include(GetGitCommitHash)
+
 project(solvespace)
 set(solvespace_VERSION_MAJOR 2)
 set(solvespace_VERSION_MINOR 1)
+string(SUBSTRING "${GIT_COMMIT_HASH}" 0 8 solvespace_GIT_HASH)
 
 if(NOT WIN32 AND NOT APPLE)
     set(GUI gtk2 CACHE STRING "GUI toolkit to use (one of: gtk2 gtk3)")

cmake/GetGitCommitHash.cmake

@@ -0,0 +1,35 @@
+function(get_git_commit_hash)
+    get_filename_component(GIT_DESCRIBE_CMAKE_DIR ${CMAKE_CURRENT_LIST_FILE} PATH)
+    get_filename_component(GIT_ROOT ${GIT_DESCRIBE_CMAKE_DIR} PATH)
+    set(GIT_DIR "${GIT_ROOT}/.git")
+
+    # Add a CMake configure dependency to the currently checked out revision.
+    set(GIT_DEPENDS ${GIT_DIR}/HEAD)
+    file(READ ${GIT_DIR}/HEAD HEAD_REF)
+    if(HEAD_REF MATCHES "ref: (.+)\n")
+        set(HEAD_REF ${CMAKE_MATCH_1})
+        if(EXISTS "${GIT_DIR}/${HEAD_REF}")
+            list(APPEND GIT_DEPENDS ${GIT_DIR}/${HEAD_REF})
+            file(READ ${GIT_DIR}/${HEAD_REF} HEAD_REF)
+        elseif(EXISTS "${GIT_DIR}/packed-refs")
+            list(APPEND GIT_DEPENDS ${GIT_DIR}/packed-refs)
+            file(READ "${GIT_DIR}/packed-refs" PACKED_REFS)
+            if(${PACKED_REFS} MATCHES "([0-9a-z]*) ${HEAD_REF}")
+                set(HEAD_REF ${CMAKE_MATCH_1})
+            else()
+                set(HEAD_REF "")
+            endif()
+        else()
+            set(HEAD_REF "")
+        endif()
+    endif()
+    set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS ${GIT_DEPENDS})
+
+    string(STRIP ${HEAD_REF} HEAD_REF)
+    if(HEAD_REF STREQUAL "")
+        message(WARNING "Cannot determine git HEAD")
+    else()
+        set(GIT_COMMIT_HASH ${HEAD_REF} PARENT_SCOPE)
+    endif()
+endfunction()
+get_git_commit_hash()

src/config.h.in

@@ -1,7 +1,7 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
-#define PACKAGE_VERSION "@solvespace_VERSION_MAJOR@.@solvespace_VERSION_MINOR@"
+#define PACKAGE_VERSION "@solvespace_VERSION_MAJOR@.@solvespace_VERSION_MINOR@~@solvespace_GIT_HASH@"
 
 /* MSVC includes a proper stdint.h, but only since VS2008. */
 #cmakedefine HAVE_STDINT_H

src/solvespace.cpp

@@ -786,8 +786,6 @@ void SolveSpaceUI::MenuHelp(int id) {
             Message(
 "This is SolveSpace version " PACKAGE_VERSION ".\n"
 "\n"
-"Built " __TIME__ " " __DATE__ ".\n"
-"\n"
 "For more information, see http://solvespace.com/\n"
 "\n"
 "SolveSpace is free software: you are free to modify\n"
@@ -797,7 +795,7 @@ void SolveSpaceUI::MenuHelp(int id) {
 "There is NO WARRANTY, to the extent permitted by\n"
 "law. For details, visit http://gnu.org/licenses/\n"
 "\n"
-"© 2008-2013 Jonathan Westhues and other authors.\n"
+"© 2008-2016 Jonathan Westhues and other authors.\n"
 );
             break;