Fix clang compiler warnings on FreeBSD in erts

The following are deliberately left, as I have only a list of compiler
warnings and no system to test on:
hipe/hipe_x86_signal.c:264:5: warning: no previous prototype for function '_sigaction' [-Wmissing-prototypes]
int __SIGACTION(int signum, const struct sigaction *act, struct sigaction *oldact)
    ^
hipe/hipe_x86_signal.c:222:21: note: expanded from macro '__SIGACTION'
                    ^
1 warning generated.
sys/unix/sys_float.c:835:16: warning: declaration of 'struct exception' will not be visible outside of this function [-Wvisibility]
matherr(struct exception *exc)
               ^
sys/unix/sys_float.c:835:1: warning: no previous prototype for function 'matherr' [-Wmissing-prototypes]
matherr(struct exception *exc)
^
2 warnings generated.
drivers/unix/unix_efile.c:1504:11: warning: implicit declaration of function 'sendfile' [-Wimplicit-function-declaration]
        retval = sendfile(in_fd, out_fd, *offset, SENDFILE_CHUNK_SIZE,
                 ^
1 warning generated.

1 files changed, 2 insertions, 2 deletions

diff --git a/erts/emulator/beam/erl_instrument.c b/erts/emulator/beam/erl_instrument.c
index 963c8b3c58..7f4349556c 100644
--- a/erts/emulator/beam/erl_instrument.c
+++ b/erts/emulator/beam/erl_instrument.c
@@ -775,8 +775,8 @@ Eterm erts_instr_get_memory_map(Process *proc)
     ASSERT(hp + 3 == end_hp);
 
     if (mem_anchor) {
-	for (bp = mem_anchor; bp->next; bp = bp->next);
-
+	for (bp = mem_anchor; bp->next; bp = bp->next)
+	    ;
 	ASSERT(org_mem_anchor);
 	org_mem_anchor->prev = bp; 
 	bp->next = org_mem_anchor;