[gcc r11-11047] libstdc++: Use close-on-exec for file descriptors in filesystem::copy_file

[Jonathan Wakely]

https://gcc.gnu.org/g:6152b026f6c80272391550faf2a655dac016db4e

commit r11-11047-g6152b026f6c80272391550faf2a655dac016db4e
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Jun 5 17:45:37 2023 +0100

    libstdc++: Use close-on-exec for file descriptors in filesystem::copy_file
    
    libstdc++-v3/ChangeLog:
    
            * src/filesystem/ops-common.h (do_copy_file) [O_CLOEXEC]: Set
            close-on-exec flag on file descriptors.
    
    (cherry picked from commit 7e8e071c4b64f1b6ea5ddf528724fc793a0f0e36)

Diff:
---
 libstdc++-v3/src/filesystem/ops-common.h | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/libstdc++-v3/src/filesystem/ops-common.h b/libstdc++-v3/src/filesystem/ops-common.h
index 6423bc9c2d2..d46fbbc662d 100644
--- a/libstdc++-v3/src/filesystem/ops-common.h
+++ b/libstdc++-v3/src/filesystem/ops-common.h
@@ -456,25 +456,26 @@ _GLIBCXX_BEGIN_NAMESPACE_FILESYSTEM
       int fd;
     };
 
-    int iflag = O_RDONLY;
+    int common_flags = 0;
+#ifdef O_CLOEXEC
+    common_flags |= O_CLOEXEC;
+#endif
 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
-    iflag |= O_BINARY;
+    common_flags |= O_BINARY;
 #endif
 
+    const int iflag = O_RDONLY | common_flags;
     CloseFD in = { posix::open(from, iflag) };
     if (in.fd == -1)
       {
 	ec.assign(errno, std::generic_category());
 	return false;
       }
-    int oflag = O_WRONLY|O_CREAT;
+    int oflag = O_WRONLY | O_CREAT | common_flags;
     if (options.overwrite || options.update)
       oflag |= O_TRUNC;
     else
       oflag |= O_EXCL;
-#ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
-    oflag |= O_BINARY;
-#endif
     CloseFD out = { posix::open(to, oflag, S_IWUSR) };
     if (out.fd == -1)
       {