From b3690306d812aca1f0f43a7d0ad4be8de1e27033 Mon Sep 17 00:00:00 2001
From: Dan Church <amphetamachine@gmail.com>
Date: Wed, 10 Jul 2019 14:56:57 -0500
Subject: [PATCH] Add ability to link to system Lua5.3

---
 CMakeLists.txt        | 22 ++++++++++-
 cmake/FindLua53.cmake | 90 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+), 2 deletions(-)
 create mode 100644 cmake/FindLua53.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 589367b82..ca65210e0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,6 +11,7 @@ list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake)
 
 option(FORCE_SYSTEM_FREETYPE "Use system-provided FreeType instead of internal library." OFF)
 option(FORCE_SYSTEM_BULLET   "Use system-provided BULLET instead of internal library."   OFF)
+option(FORCE_SYSTEM_LUA      "Use system-provided Lua instead of internal library." OFF)
 
 # Detect system FreeType
 
@@ -52,7 +53,23 @@ if (OPENTOMB_INTERNAL_BULLET)
     set(BULLET_LIBRARIES bullet)
 endif ()
 
-add_subdirectory(extern/lua)
+if (FORCE_SYSTEM_LUA)
+    find_package(Lua53 QUIET)
+    if (NOT LUA53_FOUND)
+        message(WARNING "Lua not found. Enabling internal Lua support.")
+        set(OPENTOMB_INTERNAL_LUA ON)
+    else()
+        set(OPENTOMB_INTERNAL_LUA OFF)
+    endif ()
+else ()
+    set(OPENTOMB_INTERNAL_LUA ON)
+endif ()
+
+if (OPENTOMB_INTERNAL_BULLET)
+    add_subdirectory(extern/lua)
+    set(LUA_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/extern/lua")
+    set(LUA_LIBRARY lua5.3)
+endif ()
 
 set(OPENTOMB_SRCS
     src/core/gui/gui_obj.c
@@ -280,6 +297,7 @@ target_include_directories(
     ${PROJECT_NAME} PRIVATE
     ${FREETYPE_INCLUDE_DIRS}
     ${BULLET_INCLUDE_DIRS}
+    ${LUA_INCLUDE_DIR}
     ${PNG_INCLUDE_DIRS}
     ${ZLIB_INCLUDE_DIRS}
     ${SDL2_INCLUDE_DIR}
@@ -291,7 +309,7 @@ target_link_libraries(
     ${PROJECT_NAME}
     ${FREETYPE_LIBRARIES}
     ${BULLET_LIBRARIES}
-    lua5.3
+    ${LUA_LIBRARY}
     ${PNG_LIBRARIES}
     ${OPENAL_LIBRARY}
     ${SDL2_LIBRARY}
diff --git a/cmake/FindLua53.cmake b/cmake/FindLua53.cmake
new file mode 100644
index 000000000..7f34e33f8
--- /dev/null
+++ b/cmake/FindLua53.cmake
@@ -0,0 +1,90 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+FindLua53
+---------
+
+
+
+Locate Lua library This module defines
+
+::
+
+  LUA53_FOUND, if false, do not try to link to Lua
+  LUA_LIBRARIES
+  LUA_INCLUDE_DIR, where to find lua.h
+  LUA_VERSION_STRING, the version of Lua found (since CMake 2.8.8)
+
+
+
+Note that the expected include convention is
+
+::
+
+  #include "lua.h"
+
+and not
+
+::
+
+  #include <lua/lua.h>
+
+This is because, the lua location is not standardized and may exist in
+locations other than lua/
+#]=======================================================================]
+
+find_path(LUA_INCLUDE_DIR lua.h
+  HINTS
+    ENV LUA_DIR
+  PATH_SUFFIXES include/lua53 include/lua5.3 include/lua-5.3 include/lua include
+  PATHS
+  ~/Library/Frameworks
+  /Library/Frameworks
+  /sw # Fink
+  /opt/local # DarwinPorts
+  /opt/csw # Blastwave
+  /opt
+)
+
+find_library(LUA_LIBRARY
+  NAMES lua53 lua5.3 lua-5.3 lua
+  HINTS
+    ENV LUA_DIR
+  PATH_SUFFIXES lib lib/lua53
+  PATHS
+  ~/Library/Frameworks
+  /Library/Frameworks
+  /sw
+  /opt/local
+  /opt/csw
+  /opt
+)
+
+if(LUA_LIBRARY)
+  # include the math library for Unix
+  if(UNIX AND NOT APPLE AND NOT BEOS AND NOT HAIKU)
+    find_library(LUA_MATH_LIBRARY m)
+    set( LUA_LIBRARIES "${LUA_LIBRARY};${LUA_MATH_LIBRARY}" CACHE STRING "Lua Libraries")
+  # For Windows and Mac, don't need to explicitly include the math library
+  else()
+    set( LUA_LIBRARIES "${LUA_LIBRARY}" CACHE STRING "Lua Libraries")
+  endif()
+endif()
+
+if(LUA_INCLUDE_DIR AND EXISTS "${LUA_INCLUDE_DIR}/lua.h")
+  file(STRINGS "${LUA_INCLUDE_DIR}/lua.h" lua_version_str REGEX "^#define[ \t]+LUA_RELEASE[ \t]+\"Lua .+\"")
+
+  string(REGEX REPLACE "^#define[ \t]+LUA_RELEASE[ \t]+\"Lua ([^\"]+)\".*" "\\1" LUA_VERSION_STRING "${lua_version_str}")
+  unset(lua_version_str)
+endif()
+
+# include(${CMAKE_MODULE_PATH}/FindPackageHandleStandardArgs.cmake)
+# handle the QUIETLY and REQUIRED arguments and set LUA_FOUND to TRUE if
+# all listed variables are TRUE
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(Lua53
+                                  REQUIRED_VARS LUA_LIBRARIES LUA_INCLUDE_DIR
+                                  VERSION_VAR LUA_VERSION_STRING)
+
+mark_as_advanced(LUA_INCLUDE_DIR LUA_LIBRARIES LUA_LIBRARY LUA_MATH_LIBRARY)
+