Add initial Lua scripting support

This is preliminary. There are still tons of issues, and any aspect
of scripting may change in the future. I decided to merge this
(preliminary) work now because it makes it easier to develop it, not
because it's done. lua.rst is clear enough about it (plus some
sarcasm).

This requires linking to Lua. Lua has no official pkg-config file, but
there are distribution specific .pc files, all with different names.
Adding a non-pkg-config based configure test was considered, but we'd
rather not.

One major complication is that libquvi links against Lua too, and if
the Lua version is different from mpv's, you will get a crash as soon
as libquvi uses Lua. (libquvi by design always runs when a file is
opened.) I would consider this the problem of distros and whoever
builds mpv, but to make things easier for users, we add a terrible
runtime test to the configure script, which probes whether libquvi
will crash. This is disabled when cross-compiling, but in that case
we hope the user knows what he is doing.

1 files changed, 4 insertions, 3 deletions

diff --git a/mpvcore/mp_core.h b/mpvcore/mp_core.h
index 4b8a5fcef9..e15ec0355e 100644
--- a/mpvcore/mp_core.h
+++ b/mpvcore/mp_core.h
@@ -166,6 +166,8 @@ typedef struct MPContext {
     struct track **tracks;
     int num_tracks;
 
+    char *track_layout_hash;
+
     // Selected tracks. NULL if no track selected.
     struct track *current_track[STREAM_TYPE_COUNT];
 
@@ -291,10 +293,9 @@ typedef struct MPContext {
     bool drop_message_shown;
 
     struct screenshot_ctx *screenshot_ctx;
-
-    char *track_layout_hash;
-
+    struct command_ctx *command_ctx;
     struct encode_lavc_context *encode_lavc_ctx;
+    struct lua_ctx *lua_ctx;
 } MPContext;