diff --git a/lib/libc/gen/ttyname.c b/lib/libc/gen/ttyname.c
index cb5f922390a3..e4a0ed4dec08 100644
--- a/lib/libc/gen/ttyname.c
+++ b/lib/libc/gen/ttyname.c
@@ -53,7 +53,6 @@ __FBSDID("$FreeBSD$");
 #include "libc_private.h"
 
 static char buf[sizeof(_PATH_DEV) + MAXNAMLEN];
-static char *oldttyname(int, struct stat *);
 static char *ttyname_threaded(int fd);
 static char *ttyname_unthreaded(int fd);
 
@@ -76,10 +75,8 @@ ttyname(int fd)
 char *
 ttyname_r(int fd, char *buf, size_t len)
 {
-	struct stat	dsb;
 	struct stat	sb;
 	char		*rval;
-	int		minlen;
 
 	rval = NULL;
 
diff --git a/lib/libc/locale/srune.c b/lib/libc/locale/srune.c
index 86d40a7cbdf9..073fd912e074 100644
--- a/lib/libc/locale/srune.c
+++ b/lib/libc/locale/srune.c
@@ -29,6 +29,7 @@ __FBSDID("$FreeBSD$");
 
 #include <limits.h>
 #include <rune.h>
+#include <string.h>
 #include <wchar.h>
 
 /*
diff --git a/lib/libc/locale/wcstold.c b/lib/libc/locale/wcstold.c
index 6228784f7b82..76158c1e7441 100644
--- a/lib/libc/locale/wcstold.c
+++ b/lib/libc/locale/wcstold.c
@@ -38,9 +38,9 @@ long double
 wcstold(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr)
 {
 	long double val;
-	char *buf, *end, *p;
+	char *buf, *end;
 	const wchar_t *wcp;
-	size_t clen, len;
+	size_t len;
 
 	while (iswspace(*nptr))
 		nptr++;
diff --git a/lib/libc/posix1e/mac.c b/lib/libc/posix1e/mac.c
index 9d29438f87b4..ded9059cdc6c 100644
--- a/lib/libc/posix1e/mac.c
+++ b/lib/libc/posix1e/mac.c
@@ -44,6 +44,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 #include <sys/mac.h>
 
@@ -182,7 +183,7 @@ mac_init_internal(int ignore_errors)
 		return (0);
 
 	while (fgets(line, LINE_MAX, file)) {
-		char *arg, *comment, *parse, *statement;
+		char *comment, *parse, *statement;
 
 		if (line[strlen(line)-1] == '\n')
 			line[strlen(line)-1] = '\0';
diff --git a/lib/libc/stdio/vfwprintf.c b/lib/libc/stdio/vfwprintf.c
index a6792883eafd..f069bae155b0 100644
--- a/lib/libc/stdio/vfwprintf.c
+++ b/lib/libc/stdio/vfwprintf.c
@@ -166,8 +166,7 @@ __xfputwc(wchar_t wc, FILE *fp)
 	char buf[MB_LEN_MAX];
 	struct __suio uio;
 	struct __siov iov;
-	size_t i, len;
-	int ret;
+	size_t len;
 
 	if ((fp->_flags & __SSTR) == 0)
 		return (__fputwc(wc, fp));