[newlib-cygwin] Fix __fp_lock_all() and __fp_unlock_all()

[Sebastian Huber]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=c4d4439c4208b75454edef0b42d5585de8ac9f47

commit c4d4439c4208b75454edef0b42d5585de8ac9f47
Author: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date:   Wed May 18 13:26:13 2022 +0200

    Fix __fp_lock_all() and __fp_unlock_all()
    
    For _REENT_GLOBAL_STDIO_STREAMS, lock/unlock all FILE objects.  In the
    repository, this function is only used by Cygwin during process forks.  Since
    Cygwin enabled _REENT_GLOBAL_STDIO_STREAMS recently, without this fix no FILE
    object at all was locked.

Diff:
---
 newlib/libc/stdio/findfp.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/newlib/libc/stdio/findfp.c b/newlib/libc/stdio/findfp.c
index ff6804d19..858c09ee3 100644
--- a/newlib/libc/stdio/findfp.c
+++ b/newlib/libc/stdio/findfp.c
@@ -329,6 +329,8 @@ __fp_lock_all (void)
 #ifndef _REENT_GLOBAL_STDIO_STREAMS
   ptr = _REENT;
   (void) _fwalk_sglue (ptr, __fp_lock, &ptr->__sglue);
+#else
+  (void) _fwalk_sglue (NULL, __fp_lock, &__sglue);
 #endif
 }
 
@@ -340,6 +342,8 @@ __fp_unlock_all (void)
 
   ptr = _REENT;
   (void) _fwalk_sglue (ptr, __fp_unlock, &ptr->__sglue);
+#else
+  (void) _fwalk_sglue (NULL, __fp_unlock, &__sglue);
 #endif
 
   __sfp_lock_release ();