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, 1 insertions, 1 deletions

diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index b51f076a5d..96f506c97c 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -5904,7 +5904,7 @@ erts_make_stub_module(Process* p, Eterm Mod, Eterm Beam, Eterm Info)
 	Eterm* tp;
 	Eterm func;
 	Eterm arity_term;
-	Uint arity;
+	Sint arity;
 	Uint native_address;
 	Eterm op;