MINOR: lua: add a compilation error message when compiled with an incompatible version

haproxy Lua support begins with Lua 5.2. In order to ease the diagnostic on
compilation error, a preprocessor error is added when an incompatible version
is used.

The compatibility is determined by the presence of LUA_VERSION_NUM and its
magic value (502 for Lua 5.2.x).

diff --git a/src/hlua.c b/src/hlua.c
index 9ded473c1c2b05a3cc43c767026ff29a3aace5eb..51e149e71087aea56cb283360dea959c6e930bfd 100644 (file)
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -4,6 +4,10 @@
 #include <lua.h>
 #include <lualib.h>
 
+#if !defined(LUA_VERSION_NUM) || LUA_VERSION_NUM < 502
+#error "Requires Lua 5.2 or later."
+#endif
+
 #include <ebpttree.h>
 
 #include <common/cfgparse.h>