[PATCH] Use F_GETFD rather than F_GETFL to check validity of file descriptor

[Ulf Hermann <ulf.hermann@qt.io>]

F_GETFD is both cheaper and easier to port, and otherwise has the same
effect here.

Signed-off-by: Ulf Hermann <ulf.hermann@qt.io>
---
 libelf/ChangeLog   | 4 ++++
 libelf/elf_begin.c | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/libelf/ChangeLog b/libelf/ChangeLog
index 23cd942..e32590a 100644
--- a/libelf/ChangeLog
+++ b/libelf/ChangeLog
@@ -1,5 +1,9 @@
 2017-04-20  Ulf Hermann  <ulf.hermann@qt.io>
 
+	* elf_begin.c: Use F_GETFD rather than F_GETFL.
+
+2017-04-20  Ulf Hermann  <ulf.hermann@qt.io>
+
 	* libelf.h: Define macros for various function attributes and use
 	them.
 
diff --git a/libelf/elf_begin.c b/libelf/elf_begin.c
index 5e9099c..6f85038 100644
--- a/libelf/elf_begin.c
+++ b/libelf/elf_begin.c
@@ -1075,7 +1075,7 @@ elf_begin (int fildes, Elf_Cmd cmd, Elf *ref)
   if (ref != NULL)
     /* Make sure the descriptor is not suddenly going away.  */
     rwlock_rdlock (ref->lock);
-  else if (unlikely (fcntl (fildes, F_GETFL) == -1 && errno == EBADF))
+  else if (unlikely (fcntl (fildes, F_GETFD) == -1 && errno == EBADF))
     {
       /* We cannot do anything productive without a file descriptor.  */
       __libelf_seterrno (ELF_E_INVALID_FILE);
-- 
2.1.4