Make lua data race free

Fixes tsan trace report between lua viewscreen and other threads running
lua without CoreSuspender lock. But I would assume similar races exists
when using lua from console thread, remote thread and vmethods same time.

depends/lua/CMakeLists.txt

@@ -95,6 +95,13 @@ LIST(APPEND SRC_LIBLUA ${HDR_LIBLUA})
 ADD_LIBRARY ( lua SHARED ${SRC_LIBLUA} )
 TARGET_LINK_LIBRARIES ( lua ${LIBS})
 
+target_include_directories(lua PRIVATE ../)
+if (MSVC)
+    target_compile_options(lua PRIVATE /FI lualimit.h)
+else ()
+    target_compile_options(lua PRIVATE -include lualimit.h)
+endif ()
+
 install(TARGETS lua
         LIBRARY DESTINATION ${DFHACK_LIBRARY_DESTINATION}
         RUNTIME DESTINATION ${DFHACK_LIBRARY_DESTINATION})

depends/lualimit.h

@@ -0,0 +1,61 @@
+/**
+Copyright © 2018 Pauli <suokkos@gmail.com>
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any
+damages arising from the use of this software.
+
+Permission is granted to anyone to use this software for any
+purpose, including commercial applications, and to alter it and
+redistribute it freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must
+   not claim that you wrote the original software. If you use this
+   software in a product, an acknowledgment in the product
+   documentation would be appreciated but is not required.
+
+2. Altered source versions must be plainly marked as such, and
+   must not be misrepresented as being the original software.
+
+3. This notice may not be removed or altered from any source
+   distribution.
+ */
+
+#pragma once
+
+#ifdef _MSC_VER
+#include <windows.h>
+#else
+#include <pthread.h>
+#endif
+
+#include <stdlib.h>
+
+/*! \file lualimit.h
+ * dfhack specific lua porting header that overrides lua defaults for thread
+ * safety.
+ */
+
+#ifdef _MSC_VER
+typedef CRITICAL_SECTION mutex_t;
+#else
+typedef pthread_mutex_t mutex_t;
+#endif
+
+struct lua_extra_state {
+    mutex_t* mutex;
+};
+
+#define luai_mutex(L) ((lua_extra_state*)lua_getextraspace(L))->mutex
+
+#ifdef _MSC_VER
+#define luai_userstateopen(L) luai_mutex(L) = (mutex_t*)malloc(sizeof(mutex_t)); InitializeCriticalSection(luai_mutex(L))
+#define luai_userstateclose(L) lua_unlock(L); DeleteCriticalSection(luai_mutex(L)); free(luai_mutex(L))
+#define lua_lock(L) EnterCriticalSection(luai_mutex(L))
+#define lua_unlock(L) LeaveCriticalSection(luai_mutex(L))
+#else
+#define luai_userstateopen(L) luai_mutex(L) = (mutex_t*)malloc(sizeof(mutex_t)); *luai_mutex(L) = PTHREAD_MUTEX_INITIALIZER
+#define luai_userstateclose(L) lua_unlock(L); pthread_mutex_destroy(luai_mutex(L)); free(luai_mutex(L))
+#define lua_lock(L) pthread_mutex_lock(luai_mutex(L))
+#define lua_unlock(L) pthread_mutex_unlock(luai_mutex(L))
+#endif