[newlib-cygwin/cygwin-3_4-branch] Cygwin: dps: Fix a bug that read() could not return -1 on error.

[Takashi Yano]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=b48a497cf0c575900f7a56c55752c8b4cecc6914

commit b48a497cf0c575900f7a56c55752c8b4cecc6914
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Tue Sep 5 16:59:51 2023 +0900

    Cygwin: dps: Fix a bug that read() could not return -1 on error.

Diff:
---
 winsup/cygwin/fhandler/dsp.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler/dsp.cc b/winsup/cygwin/fhandler/dsp.cc
index d930328ce..dbe27905a 100644
--- a/winsup/cygwin/fhandler/dsp.cc
+++ b/winsup/cygwin/fhandler/dsp.cc
@@ -1188,7 +1188,9 @@ fhandler_dev_dsp::_read (void *ptr, size_t& len)
       return;
     }
 
-  audio_in_->read ((char *)ptr, (int&)len);
+  int res = len;
+  audio_in_->read ((char *)ptr, res);
+  len = (size_t)res;
 }
 
 void