PERL_GLOBAL_STRUCT_PRIVATE: fix PL_isa_DOES

I added the global string constant PL_isa_DOES recently. This caused
t/porting/libperl.t to fail under -DPERL_GLOBAL_STRUCT_PRIVATE builds.

This commit makes PL_isa_DOES be declared and defined in a similar
way to other such global constants. This is pure cargo-culting - I have no
real idea of the point of all the EXTCONST, INIT and globvar.sym stuff.

1 files changed, 6 insertions, 0 deletions

diff --git a/perl.h b/perl.h
index 867c30050d..70e12bd722 100644
--- a/perl.h
+++ b/perl.h
@@ -4799,6 +4799,12 @@ EXTCONST U8 PL_subversion
 EXTCONST char PL_uuemap[65]
   INIT("`!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_");
 
+/* a special string address whose value is "isa", but which perl knows
+ * to treat as if it were really "DOES" when printing the method name in
+ *  the "Can't call method '%s'" error message */
+EXTCONST char PL_isa_DOES[]
+  INIT("isa");
+
 #ifdef DOINIT
 EXTCONST char PL_uudmap[256] =
 #  ifdef PERL_MICRO