Tcl.xs: use STRINGIFY()/JOIN() macros from Perl

tcl.h normally does not define these macros in Tcl 9.0 (and Tcl 8.7
when TCL_NO_DEPRECATED is defined), and has allowed these macros
to already be defined since Tcl 8.4b2. Perl’s definitions for
these macros (for C compilers) are equivalent to those in tcl.h.

Author: chrstphrchvz

Tcl.xs

@@ -18,12 +18,6 @@
 #define DEBUG_REFCOUNTS 0
 #endif
 
-/*
- * Both Perl and Tcl use these macros
- */
-#undef STRINGIFY
-#undef JOIN
-
 #include <tcl.h>
 
 #ifdef USE_TCL_STUBS