Fix .def generation on Windows. (#767)
Fix .def generation on Windows. (#767)

According to the Lua's manual:

> Once it finds a C library, this searcher first uses a dynamic link facility to link the application with the library. Then it tries to find a C function inside the library to be used as the loader. The name of this C function is the string "luaopen_" concatenated with a copy of the module name where each dot is replaced by an underscore. Moreover, if the module name has a hyphen, its prefix up to (and including) the first hyphen is removed. For instance, if the module name is a.v1-b.c, the function name will be luaopen_b_c.
tarantool/luarocks,keplerproject/luarocks,keplerproject/luarocks,luarocks/luarocks,keplerproject/luarocks,luarocks/luarocks,keplerproject/luarocks,tarantool/luarocks,luarocks/luarocks,tarantool/luarocks