[newlib-cygwin] Cygwin: syscalls.cc: remove ".dll" from blessed_executable_suffixes

[Ken Brown <kbrown@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=c2aa5b6d74139cc2236f4cdf415d7a133a61042d

commit c2aa5b6d74139cc2236f4cdf415d7a133a61042d
Author: Ken Brown <kbrown@cornell.edu>
Date:   Wed Aug 3 16:45:23 2022 -0400

    Cygwin: syscalls.cc: remove ".dll" from blessed_executable_suffixes
    
    This reverts commit d9e9c7b5a7.  The latter added ".dll" to the
    blessed_executable_suffixes array because on 32-bit Windows, the
    GetBinaryType function would report that a 64-bit DLL is an
    executable, contrary to the documentation of that function.
    
    That anomaly does not exist on 64-bit Windows, so we can remove ".dll"
    from the list.  Reverting the commit does, however, change the
    behavior of the rename(2) syscall in the following unlikely situation:
    Suppose we have an executable foo.exe and we make the call
    
      rename ("foo", "bar.dll");
    
    Previously, foo.exe would be renamed to bar.dll.  So bar.dll would
    then be an executable without the .exe extension.  The new behavior is
    that foo.exe will be renamed to bar.dll.exe.  [Exception: If there
    already existed an executable (not a DLL!) with the name bar.dll, then
    .exe will not be appended.]

Diff:
---
 winsup/cygwin/globals.cc  | 1 -
 winsup/cygwin/syscalls.cc | 6 ------
 2 files changed, 7 deletions(-)

diff --git a/winsup/cygwin/globals.cc b/winsup/cygwin/globals.cc
index e8147cb5c..e909d0f8f 100644
--- a/winsup/cygwin/globals.cc
+++ b/winsup/cygwin/globals.cc
@@ -120,7 +120,6 @@ const int __collate_load_error = 0;
   extern UNICODE_STRING _RDATA ro_u_empty = _ROU (L"");
   extern UNICODE_STRING _RDATA ro_u_lnk = _ROU (L".lnk");
   extern UNICODE_STRING _RDATA ro_u_exe = _ROU (L".exe");
-  extern UNICODE_STRING _RDATA ro_u_dll = _ROU (L".dll");
   extern UNICODE_STRING _RDATA ro_u_com = _ROU (L".com");
   extern UNICODE_STRING _RDATA ro_u_scr = _ROU (L".scr");
   extern UNICODE_STRING _RDATA ro_u_sys = _ROU (L".sys");
diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
index 2a481b8e5..94cb57648 100644
--- a/winsup/cygwin/syscalls.cc
+++ b/winsup/cygwin/syscalls.cc
@@ -2098,12 +2098,6 @@ nt_path_has_executable_suffix (PUNICODE_STRING upath)
   static const PUNICODE_STRING blessed_executable_suffixes[] =
   {
     &ro_u_com,
-    &ro_u_dll,	/* Messy, messy.  Per MSDN, the GetBinaryType function is
-		   supposed to return with ERROR_BAD_EXE_FORMAT. if the file
-		   is a DLL.  On 64-bit Windows, this works as expected for
-		   32-bit and 64-bit DLLs.  On 32-bit Windows this only works
-		   for 32-bit DLLs.  For 64-bit DLLs, 32-bit Windows returns
-		   true with the type set to SCS_64BIT_BINARY. */
     &ro_u_exe,
     &ro_u_scr,
     &ro_u_sys,