Explicitly use and check for FD_CLOEXEC.

This may break places which have the FD_CLOEXEC functionality
but do not have the FD_CLOEXEC define.

In any case, using a boolean for the F_SETFD flag is icky.
Using an explicit 1 is also dubious.

1 files changed, 4 insertions, 2 deletions

diff --git a/toke.c b/toke.c
index 7a0f1b6c55..d30bfe69da 100644
--- a/toke.c
+++ b/toke.c
@@ -7039,10 +7039,12 @@ Perl_yylex(pTHX)
 		if (!GvIO(gv))
 		    GvIOp(gv) = newIO();
 		IoIFP(GvIOp(gv)) = PL_rsfp;
-#if defined(HAS_FCNTL) && defined(F_SETFD)
+#if defined(HAS_FCNTL) && defined(F_SETFD) && defined(FD_CLOEXEC)
 		{
 		    const int fd = PerlIO_fileno(PL_rsfp);
-		    fcntl(fd,F_SETFD,fd >= 3);
+                    if (fd >= 3) {
+                        fcntl(fd,F_SETFD, FD_CLOEXEC);
+                    }
 		}
 #endif
 		/* Mark this internal pseudo-handle as clean */