From 5395194ed6d2513027701ca12c231cb13971596c Mon Sep 17 00:00:00 2001
From: James R <justsomejames2@gmail.com>
Date: Tue, 27 Dec 2022 00:35:57 -0800
Subject: [PATCH] cmake: generate config.h at build time, always rebuild
 comptime.c

---
 cmake/Comptime.cmake | 13 +++++++++++++
 src/CMakeLists.txt   | 26 ++++++++++++++++++++++++++
 src/d_main.c         |  7 +------
 src/sdl/i_system.c   |  6 ------
 4 files changed, 40 insertions(+), 12 deletions(-)
 create mode 100644 cmake/Comptime.cmake

diff --git a/cmake/Comptime.cmake b/cmake/Comptime.cmake
new file mode 100644
index 000000000..c6d64efa3
--- /dev/null
+++ b/cmake/Comptime.cmake
@@ -0,0 +1,13 @@
+set(CMAKE_BINARY_DIR "${BINARY_DIR}")
+set(CMAKE_CURRENT_BINARY_DIR "${BINARY_DIR}")
+
+# Set up CMAKE path
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules/")
+
+include(GitUtilities)
+
+git_current_branch(SRB2_COMP_BRANCH)
+git_summary(SRB2_COMP_REVISION)
+git_working_tree_dirty(SRB2_COMP_UNCOMMITTED)
+
+configure_file(src/config.h.in src/config.h)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 318c9cb7e..9725b792a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -132,6 +132,32 @@ add_executable(SRB2SDL2 MACOSX_BUNDLE WIN32
 	k_roulette.c
 )
 
+# This updates the modification time for comptime.c at the
+# end of building so when the build system is ran next time,
+# that file gets flagged. comptime.c will always be rebuilt.
+#
+# This begs the question, why always rebuild comptime.c?
+# Some things like the git commit must be checked each time
+# the program is built. But the build system determines which
+# files should be rebuilt before anything else. So
+# comptime.c, which only needs to be rebuilt based on
+# information known at build time, must be told to rebuild
+# before that information can be ascertained.
+add_custom_command(
+	TARGET SRB2SDL2
+	POST_BUILD
+	COMMAND ${CMAKE_COMMAND} -E touch_nocreate ${CMAKE_CURRENT_BINARY_DIR}/comptime.c
+)
+
+# config.h is generated by this command. It should be done at
+# build time for accurate git information and before anything
+# that needs it, obviously.
+add_custom_target(_SRB2_reconf ALL
+	COMMAND ${CMAKE_COMMAND} -DGIT_EXECUTABLE=${GIT_EXECUTABLE} -DBINARY_DIR=${CMAKE_CURRENT_BINARY_DIR}/.. -P ${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Comptime.cmake
+	WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/.."
+)
+add_dependencies(SRB2SDL2 _SRB2_reconf)
+
 if("${CMAKE_COMPILER_IS_GNUCC}" AND "${CMAKE_SYSTEM_NAME}" MATCHES "Windows")
 	target_link_options(SRB2SDL2 PRIVATE "-Wl,--disable-dynamicbase")
 	if(NOT "${SRB2_CONFIG_SYSTEM_LIBRARIES}" AND NOT "${SRB2_CONFIG_SHARED_INTERNAL_LIBRARIES}")
diff --git a/src/d_main.c b/src/d_main.c
index 7b0d2a4f6..392a45ece 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -77,12 +77,6 @@
 #include "m_random.h" // P_ClearRandom
 #include "k_specialstage.h"
 
-#ifdef CMAKECONFIG
-#include "config.h"
-#else
-#include "config.h.in"
-#endif
-
 #ifdef HWRENDER
 #include "hardware/hw_main.h" // 3D View Rendering
 #endif
@@ -1446,6 +1440,7 @@ void D_SRB2Main(void)
 	mainwads++; W_VerifyFileMD5(mainwads, ASSET_HASH_MAPS_PK3);			// maps.pk3 -- 4 - If you touch this, make sure to touch up the majormods stuff below.
 	mainwads++; W_VerifyFileMd5(mainwads, ASSET_HASH_FOLLOWERS_PK3);  // followers.pk3
 #ifdef USE_PATCH_FILE
+
 	mainwads++; W_VerifyFileMD5(mainwads, ASSET_HASH_PATCH_PK3);		// patch.pk3
 #endif
 #else
diff --git a/src/sdl/i_system.c b/src/sdl/i_system.c
index 707d20427..b390b6d1e 100644
--- a/src/sdl/i_system.c
+++ b/src/sdl/i_system.c
@@ -23,12 +23,6 @@
 /// \file
 /// \brief SRB2 system stuff for SDL
 
-#ifdef CMAKECONFIG
-#include "config.h"
-#else
-#include "../config.h.in"
-#endif
-
 #include <signal.h>
 
 #ifdef _WIN32