According to the susv2 man pages I have, remove(3) should act as

rmdir(2) on directories and unlink(2) otherwise. This modification,
and most of the man page update has been obtined from OpenBSD. This
was spotted by someone on a mailing lists a few months ago, but
I've lost their mail.

Reviewed by:	sheldonh

lib/libc/stdio/remove.3

@@ -51,12 +51,17 @@
 .Sh DESCRIPTION
 The
 .Fn remove
-function
-is an alias for the 
-.Xr unlink 2
-system call.
-It deletes the file referenced by
+function removes the file or directory specified by
 .Fa path .
+.Pp
+If
+.Fa path
+specifies a directory,
+.Fn remove "path"
+is the equivalent of
+.Fn rmdir "path" .
+Otherwise, it is the equivalent of
+.Fn unlink "path" .
 .Sh RETURN VALUES
 Upon successful completion, 
 .Fn remove
@@ -70,12 +75,18 @@ The
 function
 may fail and set
 .Va errno
-for any of the errors specified for the routine
+for any of the errors specified for the routines
+.Xr lstat 2 ,
+.Xr rmdir 2
+or
 .Xr unlink 2 .
 .Sh SEE ALSO
+.Xr rmdir 2 ,
 .Xr unlink 2
 .Sh STANDARDS
 The
 .Fn remove
 function conforms to
-.St -ansiC .
+.St -ansiC
+and
+.St -xpg4.2 .

lib/libc/stdio/remove.c

@@ -42,6 +42,8 @@ static const char rcsid[] =
   "$FreeBSD$";
 #endif /* LIBC_SCCS and not lint */
 
+#include <sys/types.h>
+#include <sys/stat.h>
 #include <unistd.h>
 #include <stdio.h>
 
@@ -49,5 +51,11 @@ int
 remove(file)
 	const char *file;
 {
+	struct stat sb;
+
+	if (lstat(file, &sb) < 0)
+		return (-1);
+	if (S_ISDIR(sb.st_mode))
+		return (rmdir(file));
 	return (unlink(file));
 }