Eliminate PL_sawalias, GPf_ALIASED_SV

These two commits:

    v5.21.3-759-gff2a62e "Skip no-common-vars optimisation for aliases"
    v5.21.4-210-gc997e36 "Make list assignment respect foreach aliasing"

added a run-time mechanism to detect aliased package variables,
by either "*pkg = ...," or "for $pkg (...)", and used that information
to enable the OPpASSIGN_COMMON mechanism at runtime for detecting common
elements in a list assign, e.g.

    for $alias ($a, ...) {
        ($a,$b) = (1,$alias);
    }

The previous commit but one changed the OPpASSIGN_COMMON mechanism such
that it no longer uses PL_sawalias. So this var and the mechanism for
setting it can now be removed.

This commit removes:

    * the PL_sawalias variable
    * the GPf_ALIASED_SV GP flag
    * the SAVEt_GP_ALIASED_SV and save_aliased_sv() save type.

1 files changed, 1 insertions, 1 deletions

diff --git a/scope.h b/scope.h
index 97ef3faa91..0de5b7777a 100644
--- a/scope.h
+++ b/scope.h
@@ -21,7 +21,7 @@
 
 /* one arg */
 
-#define SAVEt_GP_ALIASED_SV	4
+/*** SPARE      	        4 ***/
 #define SAVEt_BOOL		5
 #define SAVEt_COMPILE_WARNINGS	6
 #define SAVEt_COMPPAD		7