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.

13 files changed, 28 insertions, 35 deletions

diff --git a/erts/emulator/beam/beam_bp.c b/erts/emulator/beam/beam_bp.c
index c1e11f6448..9b17de34ec 100644
--- a/erts/emulator/beam/beam_bp.c
+++ b/erts/emulator/beam/beam_bp.c
@@ -969,7 +969,7 @@ erts_trace_time_call(Process* c_p, BeamInstr* I, BpDataTime* bdt)
     if (pbt == 0) {
 	/* First call of process to instrumented function */
 	pbt = Alloc(sizeof(process_breakpoint_time_t));
-	(void *) ERTS_PROC_SET_CALL_TIME(c_p, ERTS_PROC_LOCK_MAIN, pbt);
+	(void) ERTS_PROC_SET_CALL_TIME(c_p, ERTS_PROC_LOCK_MAIN, pbt);
     } else {
 	ASSERT(pbt->pc);
 	/* add time to previous code */
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;
 
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 97c8114437..46f297fc4d 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -359,8 +359,7 @@ remote_demonitor(Process *c_p, DistEntry *dep, Eterm ref, Eterm to)
 	break;
     default:
 	ASSERT(! "Invalid dsig prepare result");
-	res = ERTS_DEMONITOR_INTERNAL_ERROR;
-	break;
+	return ERTS_DEMONITOR_INTERNAL_ERROR;
     }
 
 #ifndef ERTS_SMP
diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index 64cd93a100..98d8481b53 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -2548,9 +2548,9 @@ BIF_RETTYPE setnode_2(BIF_ALIST_2)
     /* By setting dist_entry==erts_this_dist_entry and DISTRIBUTION on
        net_kernel do_net_exist will be called when net_kernel
        is terminated !! */
-    (void *) ERTS_PROC_SET_DIST_ENTRY(net_kernel,
-				      ERTS_PROC_LOCK_MAIN,
-				      erts_this_dist_entry);
+    (void) ERTS_PROC_SET_DIST_ENTRY(net_kernel,
+				    ERTS_PROC_LOCK_MAIN,
+				    erts_this_dist_entry);
     erts_refc_inc(&erts_this_dist_entry->refc, 2);
     net_kernel->flags |= F_DISTRIBUTION;
 
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index fabddffc68..3d51c17183 100755
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -3286,7 +3286,7 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
 	else if (ERTS_IS_ATOM_STR("next_pid", BIF_ARG_1)
 		 || ERTS_IS_ATOM_STR("next_port", BIF_ARG_1)) {
 	    /* Used by node_container_SUITE (emulator) */
-	    Eterm res;
+	    Sint res;
 	    if (ERTS_IS_ATOM_STR("next_pid", BIF_ARG_1))
 		res = erts_ptab_test_next_id(&erts_proc, 0, 0);
 	    else
@@ -3644,7 +3644,7 @@ BIF_RETTYPE erts_debug_set_internal_state_2(BIF_ALIST_2)
 	    Uint next;
 
 	    if (term_to_Uint(BIF_ARG_2, &next) != 0) {
-		Eterm res;
+		Sint res;
 
 		if (ERTS_IS_ATOM_STR("next_pid", BIF_ARG_1))
 		    res = erts_ptab_test_next_id(&erts_proc, 1, next);
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;
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index ab1065aaa1..126f242fc0 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -926,7 +926,7 @@ BIF_RETTYPE erts_debug_dist_ext_to_term_2(BIF_ALIST_2)
     Eterm res;
     Eterm *hp;
     Eterm *hendp;
-    Uint hsz;
+    Sint hsz;
     ErtsDistExternal ede;
     Eterm *tp;
     Eterm real_bin;
@@ -972,7 +972,7 @@ BIF_RETTYPE erts_debug_dist_ext_to_term_2(BIF_ALIST_2)
     if (hsz < 0)
 	goto badarg;
 
-    hp = HAlloc(BIF_P, hsz);
+    hp = HAlloc(BIF_P, (Uint) hsz);
     hendp = hp + hsz;
 
     res = erts_decode_dist_ext(&hp, &MSO(BIF_P), &ede);
diff --git a/erts/emulator/beam/packet_parser.c b/erts/emulator/beam/packet_parser.c
index f1cfa8df39..1e301e3593 100644
--- a/erts/emulator/beam/packet_parser.c
+++ b/erts/emulator/beam/packet_parser.c
@@ -460,11 +460,9 @@ int packet_get_length(enum PacketParseType htype,
         hp = (struct tpkt_head*) ptr;
         if (hp->vrsn == TPKT_VRSN) {
             plen = get_int16(hp->packet_length) - hlen;
-            if (plen < 0)
-                goto error;
-        }
-        else
+        } else {
             goto error;
+	}
         goto remain;
     }
     
diff --git a/erts/emulator/drivers/common/gzio.c b/erts/emulator/drivers/common/gzio.c
index ca6d25adb4..e085c262b0 100644
--- a/erts/emulator/drivers/common/gzio.c
+++ b/erts/emulator/drivers/common/gzio.c
@@ -13,6 +13,7 @@
 #  include "config.h"
 #endif
 #include <stdio.h>
+#include <string.h> /* ssize_t on Mac OS X */
 #include <errno.h>
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
@@ -314,7 +315,7 @@ local int get_byte(s)
     if (s->z_eof) return EOF;
     if (s->stream.avail_in == 0) {
 #ifdef UNIX
-	size_t res;
+	ssize_t res;
 	errno = 0;
 	res = ERTS_GZREAD(s->file, s->inbuf, Z_BUFSIZE);
 	if (res == 0) {
@@ -487,7 +488,7 @@ erts_gzread(gzFile file, voidp buf, unsigned len)
 	}
         if (s->stream.avail_in == 0 && !s->z_eof) {
 #ifdef UNIX
-	    size_t res;
+	    ssize_t res;
 	    errno = 0;
 	    res = ERTS_GZREAD(s->file, s->inbuf, Z_BUFSIZE);
 	    if (res == 0) {
diff --git a/erts/etc/common/erlexec.c b/erts/etc/common/erlexec.c
index d865164bb0..60d7c4ce02 100644
--- a/erts/etc/common/erlexec.c
+++ b/erts/etc/common/erlexec.c
@@ -184,7 +184,6 @@ void error(char* format, ...);
 #if !defined(ERTS_HAVE_SMP_EMU)
 static void usage_notsup(const char *switchname);
 #endif
-static void usage_msg(const char *msg);
 static char **build_args_from_env(char *env_var);
 static char **build_args_from_string(char *env_var);
 static void initial_argv_massage(int *argc, char ***argv);
@@ -1132,13 +1131,6 @@ usage_notsup(const char *switchname)
 #endif
 
 static void
-usage_msg(const char *msg)
-{
-    fprintf(stderr, "%s\n", msg);
-    usage_aux();
-}
-
-static void
 usage_format(char *format, ...)
 {
     va_list args;
diff --git a/erts/etc/common/inet_gethost.c b/erts/etc/common/inet_gethost.c
index b9a0e6bde3..bef97862a3 100644
--- a/erts/etc/common/inet_gethost.c
+++ b/erts/etc/common/inet_gethost.c
@@ -2562,7 +2562,8 @@ static void debugf(char *format, ...)
     }
 #else
     /* suppress warning with 'if' */
-    if(write(2,buff,strlen(buff)));
+    if(write(2,buff,strlen(buff)))
+	;
 #endif
     va_end(ap);
 }
@@ -2585,7 +2586,8 @@ static void warning(char *format, ...)
     }
 #else
     /* suppress warning with 'if' */
-    if(write(2,buff,strlen(buff)));
+    if(write(2,buff,strlen(buff)))
+	;
 #endif
     va_end(ap);
 }
@@ -2608,7 +2610,8 @@ static void fatal(char *format, ...)
     }
 #else
     /* suppress warning with 'if' */
-    if(write(2,buff,strlen(buff)));
+    if(write(2,buff,strlen(buff)))
+	;
 #endif
     va_end(ap);
 #ifndef WIN32
diff --git a/erts/lib_src/common/erl_printf_format.c b/erts/lib_src/common/erl_printf_format.c
index fd25cce7ed..384b1b1ad7 100644
--- a/erts/lib_src/common/erl_printf_format.c
+++ b/erts/lib_src/common/erl_printf_format.c
@@ -339,7 +339,7 @@ static int fmt_double(fmtfn_t fn,void*arg,double val,
     double dexp;
     int exp;
     size_t max_size = 1;
-    size_t size;
+    int size;
     int new_fmt = fmt;
     int fpe_was_unmasked;
 
diff --git a/erts/lib_src/common/ethr_mutex.c b/erts/lib_src/common/ethr_mutex.c
index e363279f2e..d8cd691e9d 100644
--- a/erts/lib_src/common/ethr_mutex.c
+++ b/erts/lib_src/common/ethr_mutex.c
@@ -692,7 +692,7 @@ write_lock_wait(struct ethr_mutex_base_ *mtxb,
 		    goto chk_spin;
 		if (--until_yield == 0) {
 		    until_yield = ETHR_YIELD_AFTER_BUSY_LOOPS;
-		    ETHR_YIELD();
+		    (void) ETHR_YIELD();
 		}
 	    }
 
@@ -711,7 +711,7 @@ write_lock_wait(struct ethr_mutex_base_ *mtxb,
 	    ETHR_SPIN_BODY;
 	    if (--until_yield == 0) {
 		until_yield = ETHR_YIELD_AFTER_BUSY_LOOPS;
-		ETHR_YIELD();
+		(void) ETHR_YIELD();
 	    }
 	    act = ethr_atomic32_read(&mtxb->flgs);
 	    scnt--;
@@ -2161,7 +2161,7 @@ rwmutex_normal_rlock_wait(ethr_rwmutex *rwmtx, ethr_sint32_t initial)
 	    ETHR_SPIN_BODY;
 	    if (--until_yield == 0) {
 		until_yield = ETHR_YIELD_AFTER_BUSY_LOOPS;
-		ETHR_YIELD();
+		(void) ETHR_YIELD();
 	    }
 	    act = ethr_atomic32_read(&rwmtx->mtxb.flgs);
 	    scnt--;
@@ -2288,7 +2288,7 @@ rwmutex_freqread_rlock_wait(ethr_rwmutex *rwmtx,
 	    ETHR_SPIN_BODY;
 	    if (--until_yield == 0) {
 		until_yield = ETHR_YIELD_AFTER_BUSY_LOOPS;
-		ETHR_YIELD();
+		(void) ETHR_YIELD();
 	    }
 	    act = ethr_atomic32_read(&rwmtx->mtxb.flgs);
 	    scnt--;