Only expose Internals::getcwd() in miniperl

It's only used during bootstrapping for miniperl when the XS version of Cwd
is not yet available, and only needed on platforms that don't already
provide their own builtin for getcwd().

It was added in v5.30.0 with the clear warning that
    [it] may be removed or changed without notice

and is not used by any code on CPAN. (Cwd references it, but won't use it
once installed as it will have already found an XS implementation (platform
specific or generic).

Author: nwc10

Makefile.SH

@@ -498,7 +498,7 @@ shextract = $shextract
 !GROK!THIS!
 
 # Source files where we build a variant for miniperl:
-mini_special='op perl'
+mini_special='op perl universal'
 for file in $mini_special; do
     mini_special_c="$mini_special_c ${file}mini.c"
     mini_only_objs="$mini_only_objs ${file}mini\$(OBJ_EXT)"
@@ -548,7 +548,7 @@ c = $(c1) $(c2) $(c3) $(c4) $(c5) miniperlmain.c $(mini_only_src)
 
 obj1 = $(mallocobj) gv$(OBJ_EXT) toke$(OBJ_EXT) perly$(OBJ_EXT) pad$(OBJ_EXT) regcomp$(OBJ_EXT) dump$(OBJ_EXT) util$(OBJ_EXT) mg$(OBJ_EXT) reentr$(OBJ_EXT) mro_core$(OBJ_EXT) keywords$(OBJ_EXT)
 obj2 = hv$(OBJ_EXT) av$(OBJ_EXT) run$(OBJ_EXT) pp_hot$(OBJ_EXT) sv$(OBJ_EXT) pp$(OBJ_EXT) scope$(OBJ_EXT) pp_ctl$(OBJ_EXT) pp_sys$(OBJ_EXT)
-obj3 = doop$(OBJ_EXT) doio$(OBJ_EXT) regexec$(OBJ_EXT) utf8$(OBJ_EXT) taint$(OBJ_EXT) deb$(OBJ_EXT) universal$(OBJ_EXT) globals$(OBJ_EXT) perlio$(OBJ_EXT) numeric$(OBJ_EXT) mathoms$(OBJ_EXT) locale$(OBJ_EXT) pp_pack$(OBJ_EXT) pp_sort$(OBJ_EXT) caretx$(OBJ_EXT) dquote$(OBJ_EXT) time64$(OBJ_EXT)
+obj3 = doop$(OBJ_EXT) doio$(OBJ_EXT) regexec$(OBJ_EXT) utf8$(OBJ_EXT) taint$(OBJ_EXT) deb$(OBJ_EXT) globals$(OBJ_EXT) perlio$(OBJ_EXT) numeric$(OBJ_EXT) mathoms$(OBJ_EXT) locale$(OBJ_EXT) pp_pack$(OBJ_EXT) pp_sort$(OBJ_EXT) caretx$(OBJ_EXT) dquote$(OBJ_EXT) time64$(OBJ_EXT)
 
 # split the objects into 3 exclusive sets: those used by both miniperl and
 # perl, and those used by just one or the other. Doesn't include the

t/io/getcwd.t

@@ -6,17 +6,14 @@ BEGIN {
     set_up_inc('../lib');
 }
 
-use Config;
-
-$Config{d_getcwd}
-  or plan skip_all => "no getcwd";
+defined &Internals::getcwd
+  or plan skip_all => "no Internals::getcwd";
 
 my $cwd = Internals::getcwd();
-ok(!defined $cwd || $cwd ne "",
-   "Internals::getcwd() returned a reasonable result");
 
-if (defined $cwd) {
-    ok(-d $cwd, "check a success result is a directory");
+if (ok(defined $cwd, "Internals::getcwd() returned a defined result")) {
+    isnt($cwd, "", "Internals::getcwd() returned a non-empty result");
+    ok(-d $cwd, "Internals::getcwd() result is a directory");
 }
 
 done_testing();

universal.c

@@ -1,3 +1,4 @@
+#line 2 "universal.c"
 /*    universal.c
  *
  *    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
@@ -1065,7 +1066,7 @@ XS(XS_re_regexp_pattern)
     NOT_REACHED; /* NOTREACHED */
 }
 
-#ifdef HAS_GETCWD
+#if defined(HAS_GETCWD) && defined(PERL_IS_MINIPERL)
 
 XS(XS_Internals_getcwd)
 {
@@ -1273,7 +1274,7 @@ static const struct xsub_details these_details[] = {
     {"re::regnames", XS_re_regnames, ";$", 0 },
     {"re::regnames_count", XS_re_regnames_count, "", 0 },
     {"re::regexp_pattern", XS_re_regexp_pattern, "$", 0 },
-#ifdef HAS_GETCWD
+#if defined(HAS_GETCWD) && defined(PERL_IS_MINIPERL)
     {"Internals::getcwd", XS_Internals_getcwd, "", 0 },
 #endif
     {"Tie::Hash::NamedCapture::_tie_it", XS_NamedCapture_tie_it, NULL, 0 },