Fix compilation issues with recent LuaJIT 2.1.

Protect macros with `#ifndef`.
Use "compat53" prefix instead of "lua" prefix for the mode where
static versions of the C API functions are created.

Fixes #19.

3 files changed, 44 insertions, 27 deletions

diff --git a/README.md b/README.md
index 8c7b058..25bc911 100644
--- a/README.md
+++ b/README.md
@@ -72,7 +72,11 @@ your project:
   compatibility functions in your code. You have to compile and link
   `compat-5.3.c` to your project yourself. You can change the way the
   functions are exported using the `COMPAT53_API` macro (e.g. if you need
-  some `__declspec` magic).
+  some `__declspec` magic). While it is technically possible to use
+  the "lua" prefix (and it looks better in the debugger), this is
+  discouraged because LuaJIT has started to implement its own Lua 5.2+
+  C API functions, and with the "lua" prefix you'd violate the
+  one-definition rule with recent LuaJIT versions.
 
 ## What's implemented
 
diff --git a/c-api/compat-5.3.c b/c-api/compat-5.3.c
index d7d127f..b913196 100644
--- a/c-api/compat-5.3.c
+++ b/c-api/compat-5.3.c
@@ -263,7 +263,6 @@ COMPAT53_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len) {
 }
 
 
-#if !defined(COMPAT53_IS_LUAJIT)
 static int compat53_countlevels (lua_State *L) {
   lua_Debug ar;
   int li = 1, le = 1;
@@ -418,7 +417,6 @@ COMPAT53_API int luaL_execresult (lua_State *L, int stat) {
     return 3;
   }
 }
-#endif /* not COMPAT53_IS_LUAJIT */
 
 
 COMPAT53_API void luaL_buffinit (lua_State *L, luaL_Buffer_53 *B) {
diff --git a/c-api/compat-5.3.h b/c-api/compat-5.3.h
index ba90d81..0083eb4 100644
--- a/c-api/compat-5.3.h
+++ b/c-api/compat-5.3.h
@@ -24,10 +24,9 @@ extern "C" {
 #  undef COMPAT53_INCLUDE_SOURCE
 #else /* COMPAT53_PREFIX */
 /* - make all functions static and include the source.
- * - don't mess with the symbol names of functions
  * - compat-5.3.c doesn't need to be compiled (and linked) separately
  */
-#  define COMPAT53_PREFIX lua
+#  define COMPAT53_PREFIX compat53
 #  undef COMPAT53_API
 #  if defined(__GNUC__) || defined(__clang__)
 #    define COMPAT53_API __attribute__((__unused__)) static
@@ -55,25 +54,39 @@ extern "C" {
  * luaL_loadfilex
  */
 
-/* PUC-Rio Lua uses lconfig_h as include guard for luaconf.h,
- * LuaJIT uses luaconf_h. If you use PUC-Rio's include files
- * but LuaJIT's library, you will need to define the macro
- * COMPAT53_IS_LUAJIT yourself! */
-#if !defined(COMPAT53_IS_LUAJIT) && defined(luaconf_h)
-#  define COMPAT53_IS_LUAJIT
+#ifndef LUA_OK
+#  define LUA_OK 0
+#endif
+#ifndef LUA_OPADD
+#  define LUA_OPADD 0
+#endif
+#ifndef LUA_OPSUB
+#  define LUA_OPSUB 1
+#endif
+#ifndef LUA_OPMUL
+#  define LUA_OPMUL 2
+#endif
+#ifndef LUA_OPDIV
+#  define LUA_OPDIV 3
+#endif
+#ifndef LUA_OPMOD
+#  define LUA_OPMOD 4
+#endif
+#ifndef LUA_OPPOW
+#  define LUA_OPPOW 5
+#endif
+#ifndef LUA_OPUNM
+#  define LUA_OPUNM 6
+#endif
+#ifndef LUA_OPEQ
+#  define LUA_OPEQ 0
+#endif
+#ifndef LUA_OPLT
+#  define LUA_OPLT 1
+#endif
+#ifndef LUA_OPLE
+#  define LUA_OPLE 2
 #endif
-
-#define LUA_OK 0
-#define LUA_OPADD 0
-#define LUA_OPSUB 1
-#define LUA_OPMUL 2
-#define LUA_OPDIV 3
-#define LUA_OPMOD 4
-#define LUA_OPPOW 5
-#define LUA_OPUNM 6
-#define LUA_OPEQ 0
-#define LUA_OPLT 1
-#define LUA_OPLE 2
 
 typedef size_t lua_Unsigned;
 
@@ -106,10 +119,14 @@ COMPAT53_API void lua_copy (lua_State *L, int from, int to);
 #define lua_len COMPAT53_CONCAT(COMPAT53_PREFIX, _len)
 COMPAT53_API void lua_len (lua_State *L, int i);
 
-#define luaL_newlibtable(L, l) \
+#ifndef luaL_newlibtable
+#  define luaL_newlibtable(L, l) \
   (lua_createtable(L, 0, sizeof(l)/sizeof(*(l))-1))
-#define luaL_newlib(L, l) \
+#endif
+#ifndef luaL_newlib
+#  define luaL_newlib(L, l) \
   (luaL_newlibtable(L, l), luaL_register(L, NULL, l))
+#endif
 
 #define lua_pushglobaltable(L) \
   lua_pushvalue(L, LUA_GLOBALSINDEX)
@@ -152,7 +169,6 @@ COMPAT53_API void *luaL_testudata (lua_State *L, int i, const char *tname);
 #define luaL_tolstring COMPAT53_CONCAT(COMPAT53_PREFIX, L_tolstring)
 COMPAT53_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len);
 
-#if !defined(COMPAT53_IS_LUAJIT)
 #define luaL_traceback COMPAT53_CONCAT(COMPAT53_PREFIX, L_traceback)
 COMPAT53_API void luaL_traceback (lua_State *L, lua_State *L1, const char *msg, int level);
 
@@ -161,7 +177,6 @@ COMPAT53_API int luaL_fileresult (lua_State *L, int stat, const char *fname);
 
 #define luaL_execresult COMPAT53_CONCAT(COMPAT53_PREFIX, L_execresult)
 COMPAT53_API int luaL_execresult (lua_State *L, int stat);
-#endif /* COMPAT53_IS_LUAJIT */
 
 #define lua_callk(L, na, nr, ctx, cont) \
   ((void)(ctx), (void)(cont), lua_call(L, na, nr))