From b3b23e8278228fdf5fdcb697cb597db212f5bfbf Mon Sep 17 00:00:00 2001
From: Pauli <suokkos@gmail.com>
Date: Mon, 25 Jun 2018 15:25:13 +0300
Subject: [PATCH] Add dependency from git-describe.h to DFHackVersion.cpp

Using add_custom_command allows cmake to track dependency from command
to git-describe.h that is implicit dependency of DFHackVersion.cpp.

The change also fixes issues if there is multiple build directories and
git-describe.h missing but git-dsecribe.h.tmp is present.
---
 library/CMakeLists.txt     | 17 ++++++++++++++---
 library/git-describe.cmake |  5 ++---
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 22ed67711..dcade1fe5 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -297,7 +297,14 @@ ELSE(WIN32)
   SET(PROJECT_LIBS psapi dfhack-md5 ${DFHACK_TINYXML} dfhack-tinythread)
 ENDIF()
 
-ADD_LIBRARY(dfhack-version STATIC DFHackVersion.cpp)
+set(VERSION_SRCS DFHackVersion.cpp)
+set(VERSION_HDRS git-describe.h)
+
+SET_SOURCE_FILES_PROPERTIES(${VERSION_HDRS} PROPERTIES HEADER_FILE_ONLY TRUE)
+
+LIST(APPEND VERSION_SRCS ${VERSION_HDRS})
+
+ADD_LIBRARY(dfhack-version STATIC ${VERSION_SRCS})
 SET_PROPERTY(TARGET dfhack-version APPEND PROPERTY COMPILE_DEFINITIONS
     DFHACK_VERSION="${DFHACK_VERSION}"
     DF_VERSION="${DF_VERSION}"
@@ -312,15 +319,19 @@ ENDIF()
 
 # always re-run git-describe if cmake is re-run (e.g. if build ID or version changes)
 EXECUTE_PROCESS(COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_SOURCE_DIR}/git-describe.cmake)
-ADD_CUSTOM_TARGET(git-describe
+target_include_directories(dfhack-version PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+
+ADD_CUSTOM_COMMAND(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/git-describe.h always_rebuild
     COMMAND ${CMAKE_COMMAND}
         -D dfhack_SOURCE_DIR:STRING=${dfhack_SOURCE_DIR}
+        -D git_describe_h:STRING=${CMAKE_CURRENT_BINARY_DIR}/git-describe.h
         -D GIT_EXECUTABLE:STRING=${GIT_EXECUTABLE}
         -D DFHACK_BUILD_ID:STRING=${DFHACK_BUILD_ID}
         -P ${CMAKE_CURRENT_SOURCE_DIR}/git-describe.cmake
     COMMENT "Obtaining git commit information"
+    DEPENDS ${GIT_EXECUTABLE}
+    VERBATIM
 )
-ADD_DEPENDENCIES(dfhack-version git-describe)
 
 ADD_LIBRARY(dfhack SHARED ${PROJECT_SOURCES})
 ADD_DEPENDENCIES(dfhack generate_headers generate_proto_core)
diff --git a/library/git-describe.cmake b/library/git-describe.cmake
index 6650dbde4..7cf211674 100644
--- a/library/git-describe.cmake
+++ b/library/git-describe.cmake
@@ -2,10 +2,9 @@ if(NOT EXISTS ${dfhack_SOURCE_DIR}/.git/index OR NOT EXISTS ${dfhack_SOURCE_DIR}
     MESSAGE(FATAL_ERROR "Could not find git index file(s)")
 endif()
 
-set(git_describe_tmp_h ${dfhack_SOURCE_DIR}/library/include/git-describe.tmp.h)
-set(git_describe_h ${dfhack_SOURCE_DIR}/library/include/git-describe.h)
+set(git_describe_tmp_h ${git_describe_h}.tmp)
 
-if(EXISTS ${git_describe_tmp_h} AND
+if(EXISTS ${git_describe_tmp_h} AND EXISTS ${git_describe_h} AND
         NOT(${dfhack_SOURCE_DIR}/.git/index IS_NEWER_THAN ${git_describe_tmp_h}) AND
         NOT(${dfhack_SOURCE_DIR}/.git/modules/library/xml/index IS_NEWER_THAN ${git_describe_tmp_h}) AND
         NOT(${dfhack_SOURCE_DIR}/library/git-describe.cmake IS_NEWER_THAN ${git_describe_tmp_h}))