diff --git a/lib/libarchive/archive_platform.h b/lib/libarchive/archive_platform.h
index ee6c08e00914..0f651e87bda6 100644
--- a/lib/libarchive/archive_platform.h
+++ b/lib/libarchive/archive_platform.h
@@ -49,6 +49,7 @@
 #define HAVE_CHFLAGS 1
 #define HAVE_LUTIMES 1
 #define HAVE_LCHMOD 1
+#define HAVE_POSIX_STRERROR_R 1
 #define ARCHIVE_ERRNO_FILE_FORMAT EFTYPE
 #define ARCHIVE_ERRNO_PROGRAMMER EINVAL
 #define ARCHIVE_ERRNO_MISC (-1)
@@ -85,6 +86,7 @@
 #define st_atimespec st_atim
 #define st_mtimespec st_mtim
 #define st_ctimespec st_ctim
+#define HAVE_GLIBC_STRERROR_R 1
 #endif
 
 /*
diff --git a/lib/libarchive/archive_read_support_format_tar.c b/lib/libarchive/archive_read_support_format_tar.c
index 24c7f42e26f7..47bfc55898e9 100644
--- a/lib/libarchive/archive_read_support_format_tar.c
+++ b/lib/libarchive/archive_read_support_format_tar.c
@@ -81,9 +81,7 @@ struct tar {
 	int			 header_recursion_depth;
 };
 
-static size_t	UTF8_mbrtowc(wchar_t * __restrict pwc,
-		    const char * __restrict s, size_t n,
-		    mbstate_t * __restrict ps __unused);
+static size_t	UTF8_mbrtowc(wchar_t *pwc, const char *s, size_t n);
 static int	archive_block_is_null(const unsigned char *p);
 static int	header_Solaris_ACL(struct archive *,  struct tar *,
 		    struct archive_entry *, struct stat *, const void *);
@@ -640,9 +638,10 @@ static int
 header_pax_extensions(struct archive *a, struct tar *tar,
     struct archive_entry *entry, struct stat *st, const void *h)
 {
-	read_body_to_string(a, &(tar->pax_header), h);
 	int err, err2;
 
+	read_body_to_string(a, &(tar->pax_header), h);
+
 	/* Parse the next header. */
 	err = tar_read_header(a, tar, entry, st);
 
@@ -1085,7 +1084,7 @@ utf8_decode(wchar_t *dest, const char *src, size_t length)
 
 	err = 0;
 	while(length > 0) {
-		n = UTF8_mbrtowc(dest, src, length, NULL);
+		n = UTF8_mbrtowc(dest, src, length);
 		if (n == 0)
 			break;
 		if (n > 8) {
@@ -1106,8 +1105,7 @@ utf8_decode(wchar_t *dest, const char *src, size_t length)
  * Copied from FreeBSD libc/locale.
  */
 static size_t
-UTF8_mbrtowc(wchar_t * __restrict pwc, const char * __restrict s, size_t n,
-    mbstate_t * __restrict ps __unused)
+UTF8_mbrtowc(wchar_t *pwc, const char *s, size_t n)
 {
         int ch, i, len, mask;
         wchar_t lbound, wch;
diff --git a/lib/libarchive/archive_util.c b/lib/libarchive/archive_util.c
index 587e8af803b4..11d151abd887 100644
--- a/lib/libarchive/archive_util.c
+++ b/lib/libarchive/archive_util.c
@@ -84,6 +84,7 @@ archive_set_error(struct archive *a, int error_number, const char *fmt, ...)
 {
 	va_list ap;
 	char errbuff[512];
+	char *errp;
 
 	a->archive_error_number = error_number;
 	if (fmt == NULL) {
@@ -95,8 +96,16 @@ archive_set_error(struct archive *a, int error_number, const char *fmt, ...)
 	archive_string_vsprintf(&(a->error_string), fmt, ap);
 	if(error_number > 0) {
 		archive_strcat(&(a->error_string), ": ");
+#if defined(HAVE_GLIBC_STRERROR_R)
+		errp = strerror_r(error_number, errbuff, sizeof(errbuff));
+#elif defined(HAVE_POSIX_STRERROR_R)
 		strerror_r(error_number, errbuff, sizeof(errbuff));
-		archive_strcat(&(a->error_string), errbuff);
+		errp = errbuff;
+#else
+		/* Note: this is not threadsafe! */
+		errp = strerror(error_number);
+#endif
+		archive_strcat(&(a->error_string), errp);
 	}
 	a->error = a->error_string.s;
 	va_end(ap);