Integrate change #9030 from maintperl into mainline.

Subject: [PATCH 5.6.1] OS/2 cleanup

p4raw-link: @9030 on //depot/maint-5.6/perl: 2105755b4e61318e9489b9a118af8e270a8bc735

p4raw-id: //depot/perl@9031
p4raw-branched: from //depot/maint-5.6/perl@9029 'branch in'
	os2/os2add.sym
p4raw-integrated: from //depot/maint-5.6/perl@9029 'copy in'
	os2/Changes os2/OS2/REXX/REXX.pm os2/OS2/REXX/t/rx_cmprt.t
	os2/os2.sym (@5902..) os2/Makefile.SHs (@8153..)
	os2/OS2/REXX/REXX.xs os2/os2ish.h (@8606..) 'merge in'
	lib/ExtUtils/MM_OS2.pm os2/OS2/REXX/Makefile.PL (@5902..)
	MANIFEST (@8986..) makedef.pl (@8987..) os2/os2.c (@9016..)
	lib/ExtUtils/MM_Unix.pm (@9028..)

1 files changed, 65 insertions, 0 deletions

diff --git a/os2/Changes b/os2/Changes
index e56b7081ff..e72e0bd2cd 100644
--- a/os2/Changes
+++ b/os2/Changes
@@ -322,3 +322,68 @@ after 5.005_62:
 	  (alas, uppercased - but with /);
 	t/io/fs.t was failing on HPFS386;
 	Remove extra ';' from defines for MQ operations.
+
+pre 5.6.1:
+	Resolved: "Bad free()" messages (e.g., from DB_File) with -Zomf build.
+	   The reason was: when an extension DLL was linked, the order of
+	   libraries was similar to this:
+		f1.obj f2.obj libperl.lib -llibr1 -llibr2
+	   (with C RTL implicitly after this).  When libperl.lib overrides
+	   some C RTL functions, they are correctly resolved when mentioned
+	   in f1.obj and f2.obj.  However, the resolution for libr1.lib and
+	   libr2.lib is implementation-dependent.
+
+	   With -Zomf linking the symbols are resolved for libr1.lib and
+	   libr2.lib *only if* they reside in .obj-file-sections of libperl.lib
+	   which were already "picked up" for symbols in f1.obj f2.obj.
+	   However, libperl.lib is an import library for a .DLL, so *each
+	   symbol in libperl.lib sits in its own pseudo-section*!
+
+	   Corollary: only those symbol from libperl.lib which were already
+	   mentioned in f1.obj f2.obj would be used for libr1.lib and
+	   libr2.lib.  Example: if f1.obj f2.obj do not mention calloc() but
+	   libr1.lib and libr2.lib do, then .lib's will get calloc() of C RTL,
+	   not one of libperl.lib.
+
+	   Solution: create a small duplicate of libperl.lib with overriding
+	   symbols only.  Put it *after* -llibr1 -llibr2 on the link line.
+	   Map strdup() and putenv() to Perl_strdup() and Perl_putenv()
+	   inside this library.
+
+	Resolved: rmdir() and mkdir() do not accept trailing slashes.
+	   Wrappers are implemented.
+	Resolved: when loading modules, FP mask may be erroneously changed by
+	   _DLLInitTerm() (e.g., TCP32IP).
+		Solutions: a) dlopen() saves/restores the FP mask.
+			   b) When starting, reset FP mask to a sane value
+				(if the DLL was compile-time linked).
+	New functions in package OS2:
+		unsigned _control87(unsigned new,unsigned mask)	# as in EMX
+		unsigned get_control87()
+		# with default values good for handling exception mask:
+		unsigned set_control87_em(new=MCW_EM,mask=MCW_EM)
+	    Needed to guard against other situations when the FP mask is
+	    stompted upon.  Apparently, IBM used a compiler (for some period
+	    of time around '95?) which changes FP mask right and left...
+	Resolved: $^X was always uppercased (cosmetic).  Solution:
+	    use argv[0] if it differs from what the OS returns only in case.
+	Resolved: when creating PM message queues, WinCancelShutdown() was
+	    not called even if the application said that it would not serve
+	    messages in this queue.  Could result in PM refusing to shutdown.
+
+	    Solution: resolve WinCancelShutdown at run time, keep the refcount
+	    of who is going to serve the queue.
+	Resolved: Perl_Deregister_MQ() segfaulted (pid/tid not initialized).
+	Resolved: FillWinError() would not fetch the error.
+	    Solution: resolve WinGetLastError at run time, call it.
+	Resolved: OS2::REXX would ignore arguments given to a Perl function
+	    imported into the REXX compartment via REXX_eval_with().
+	Resolved: OS2::REXX would treat arguments given to a Perl function
+	    imported into the REXX compartment via _register() as ASCIIZ
+	    strings inside of binary strings.
+	Resolved: OS2::REXX did not document _register().
+	Resolved: OS2::REXX would not report the error to REXX if an error
+	    condition appeared during a call to Perl function from REXX
+	    compartment.  As a result, the return string was not initialized.
+	A complete example of a mini-application added to OS2::REXX.
+