Don't shadow standard headers

@italic on the AUR stated that bfs from the AUR fails to build on
Manjaro.  From the build log, it seems like <time.h> doesn't get
included properly.  I assume it's picking up ./time.h instead.

I couldn't reproduce the build issue in the default configuration, but
it does fail with EXTRA_CFLAGS="-I." which isn't good.  So rename
everything with an x prefix to stop clashing.

Link: https://aur.archlinux.org/packages/bfs#comment-856102
Link: https://paste.rs/eqR

1 files changed, 1 insertions, 1 deletions

diff --git a/exec.c b/exec.c
index 4cfb2e0..505e51c 100644
--- a/exec.c
+++ b/exec.c
@@ -20,8 +20,8 @@
 #include "color.h"
 #include "diag.h"
 #include "dstring.h"
-#include "spawn.h"
 #include "util.h"
+#include "xspawn.h"
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>