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, 6 insertions, 3 deletions

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