POSIX: delete the L_tmpnam and L_tmpname symbols

The history here is relatively complicated.

The L_tmpname symbol is neither specified by POSIX or defined by traditional
Unix system; it's simply a typo for L_tmpnam, first introduced in Perl 5.0.

Commit 33f01dd (part of Perl 5.6) added
support for L_tmpnam, treating L_tmpname as a back-compat synonym. However,
no version of Perl has ever made L_tmpnam exportable, even at explicit
request; using that symbol has always required using its fully-qualified
POSIX::L_tmpnam name.

During the 5.8 development cycle, an apparently-unintended consequence of
various improvements to the way that POSIX.pm generates and exports constants
meant that L_tmpname stopped working. It continued to be exportable, but
trying to use the constant yielded an exception saying "Your vendor has not
defined POSIX macro L_tmpname". (This isn't exactly incorrect, of course: no
vendor defines the macro L_tmpname!)

At this point, therefore, there seems little benefit in trying to resurrect
support for the L_tmpname typo: it's impossible for any program running on
5.8.0 or later to have successfully used it.

There's perhaps an argument for making L_tmpnam exportable at this point,
since it does work when called by its full-qualified name. One option would
be to add it to @EXPORT_OK; but that is explicitly counselled against by the
POSIX.pm comments summarising the policy on symbol exports, which recommend
adding a new export tag instead. In this case, the obvious tag to use is
:stdio_h (which already exists), since the C-level symbol is provided by the
<stdio.h> header.

However, that doesn't seem worth it to me. The only possible use of L_tmpnam
is to create a buffer of a size suitable for passing to the tmpnam() C
function (which is presumably why nobody's noticed in the last fifteen years
that the symbol isn't actually exported). Furthermore, the POSIX.pm wrapper
for tmpnam() itself was deleted by 19fc296,
a few days ago, so merely deleting this additional symbol seems correct.

Author: arc

ext/POSIX/Makefile.PL

@@ -48,7 +48,7 @@ my @names =
       EUSERS EWOULDBLOCK EXDEV FILENAME_MAX F_OK HUPCL ICANON ICRNL IEXTEN
       IGNBRK IGNCR IGNPAR INLCR INPCK INT_MAX INT_MIN ISIG ISTRIP IXOFF IXON
       LC_ALL LC_COLLATE LC_CTYPE LC_MESSAGES LC_MONETARY LC_NUMERIC LC_TIME
-      LINK_MAX LONG_MAX LONG_MIN L_ctermid L_cuserid L_tmpnam MAX_CANON
+      LINK_MAX LONG_MAX LONG_MIN L_ctermid L_cuserid MAX_CANON
       MAX_INPUT MB_LEN_MAX MSG_CTRUNC MSG_DONTROUTE MSG_EOR MSG_OOB MSG_PEEK
       MSG_TRUNC MSG_WAITALL NAME_MAX NCCS NGROUPS_MAX NOFLSH OPEN_MAX OPOST
       PARENB PARMRK PARODD PATH_MAX PIPE_BUF RAND_MAX R_OK SCHAR_MAX
@@ -74,8 +74,6 @@ my @names =
    {name=>"SIG_DFL", value=>"PTR2IV(SIG_DFL)", not_constant=>1},
    {name=>"SIG_ERR", value=>"PTR2IV(SIG_ERR)", not_constant=>1},
    {name=>"SIG_IGN", value=>"PTR2IV(SIG_IGN)", not_constant=>1},
-   # L_tmpnam[e] was a typo--retained for compatibility
-   {name=>"L_tmpname", value=>"L_tmpnam"},
    {name=>"NULL", value=>"0"},
    {name=>"_POSIX_JOB_CONTROL", type=>"YES", default=>["IV", "0"]},
    {name=>"_POSIX_SAVED_IDS", type=>"YES", default=>["IV", "0"]},

ext/POSIX/lib/POSIX.pm

@@ -4,7 +4,7 @@ use warnings;
 
 our ($AUTOLOAD, %SIGRT);
 
-our $VERSION = '1.68';
+our $VERSION = '1.69';
 
 require XSLoader;
 
@@ -24,6 +24,7 @@ sub usage { croak "Usage: POSIX::$_[0]" }
 XSLoader::load();
 
 my %replacement = (
+    L_tmpnam    => undef,
     atexit      => 'END {}',
     atof        => undef,
     atoi        => undef,
@@ -337,7 +338,7 @@ my %default_export_tags = ( # cf. exports policy below
     stddef_h =>	[qw(NULL offsetof)],
 
     stdio_h =>	[qw(BUFSIZ EOF FILENAME_MAX L_ctermid L_cuserid
-		L_tmpname NULL SEEK_CUR SEEK_END SEEK_SET
+		NULL SEEK_CUR SEEK_END SEEK_SET
 		STREAM_MAX TMP_MAX stderr stdin stdout
 		clearerr fclose fdopen feof ferror fflush fgetc fgetpos
 		fgets fopen fprintf fputc fputs fread freopen

ext/POSIX/lib/POSIX.pod

@@ -2593,7 +2593,7 @@ C<EXIT_FAILURE> C<EXIT_SUCCESS> C<MB_CUR_MAX> C<RAND_MAX>
 
 =item Constants
 
-C<BUFSIZ> C<EOF> C<FILENAME_MAX> C<L_ctermid> C<L_cuserid> C<L_tmpname> C<TMP_MAX>
+C<BUFSIZ> C<EOF> C<FILENAME_MAX> C<L_ctermid> C<L_cuserid> C<TMP_MAX>
 
 =back
 

ext/POSIX/t/export.t

@@ -49,7 +49,7 @@ my %expect = (
             LC_CTYPE LC_MESSAGES LC_MONETARY LC_NUMERIC LC_TIME LDBL_DIG
             LDBL_EPSILON LDBL_MANT_DIG LDBL_MAX LDBL_MAX_10_EXP
             LDBL_MAX_EXP LDBL_MIN LDBL_MIN_10_EXP LDBL_MIN_EXP LINK_MAX
-            LONG_MAX LONG_MIN L_ctermid L_cuserid L_tmpname MAX_CANON
+            LONG_MAX LONG_MIN L_ctermid L_cuserid MAX_CANON
             MAX_INPUT MB_CUR_MAX MB_LEN_MAX NAME_MAX NCCS NDEBUG
             NGROUPS_MAX NOFLSH NULL OPEN_MAX OPOST O_ACCMODE O_APPEND
             O_CREAT O_EXCL O_NOCTTY O_NONBLOCK O_RDONLY O_RDWR O_TRUNC
@@ -148,7 +148,7 @@ my %expect = (
             localtime log mkdir nice open opendir pipe printf rand
             read readdir rename rewinddir rmdir sin sleep sprintf sqrt
             srand stat system time times umask unlink utime wait
-            waitpid write
+            waitpid write L_tmpnam
         ),
         # this stuff was added in 5.21
         # (though an oversight meant that lround wasn't listed here

ext/POSIX/t/unimplemented.t

@@ -88,6 +88,7 @@ foreach ([atexit => 'C-specific: use END {} instead'],
 	 [vfprintf => 'C-specific, stopped'],
 	 [vprintf => 'C-specific, stopped'],
 	 [vsprintf => 'C-specific, stopped'],
+	 [L_tmpnam => 'C-specific, stopped'],
 	) {
     my ($func, $action) = @$_;
     my $expect = ref $action