diff --git a/usr.sbin/config/config.h b/usr.sbin/config/config.h
--- a/usr.sbin/config/config.h
+++ b/usr.sbin/config/config.h
@@ -263,9 +263,11 @@
 extern STAILQ_HEAD(file_list_head, file_list) ftab;
 
 extern STAILQ_HEAD(files_name_head, files_name) fntab;
+extern STAILQ_HEAD(options_files_name_head, files_name) optfntab;
 
 extern int	debugging;
 extern int	found_defaults;
+extern int	verbose;
 
 extern int	maxusers;
 extern int	versreq;
diff --git a/usr.sbin/config/config.5 b/usr.sbin/config/config.5
--- a/usr.sbin/config/config.5
+++ b/usr.sbin/config/config.5
@@ -241,6 +241,15 @@
 and return to the current file after
 .Ar filename
 is successfully processed.
+.\" -------- INCLUDEOPTIONS --------
+.Pp
+.It .Ic includeoptions Ar filename
+Specifies a file containing a list of additional options
+specific to that kernel configuration file.
+This is useful for build environments that need to add
+custom options and is often used in conjunction with the
+.Ic makeoption
+directive.
 .\" -------- MACHINE --------
 .Pp
 .It Ic machine Ar arch Op Ar cpuarch
diff --git a/usr.sbin/config/config.8 b/usr.sbin/config/config.8
--- a/usr.sbin/config/config.8
+++ b/usr.sbin/config/config.8
@@ -36,7 +36,7 @@
 .Nd build system configuration files
 .Sh SYNOPSIS
 .Nm
-.Op Fl CVgp
+.Op Fl CVgpv
 .Op Fl I Ar path
 .Op Fl d Ar destdir
 .Op Fl s Ar srcdir
@@ -102,6 +102,8 @@
 This option makes sense only if
 .Cd "options INCLUDE_CONFIG_FILE"
 entry was present in your configuration file.
+.It Fl v
+Turns on verbose output.
 .It Ar SYSTEM_NAME
 Specify the name of the system configuration file
 containing device specifications, configuration options
diff --git a/usr.sbin/config/config.y b/usr.sbin/config/config.y
--- a/usr.sbin/config/config.y
+++ b/usr.sbin/config/config.y
@@ -24,6 +24,7 @@
 %token	NOMAKEOPTION 
 %token	SEMICOLON
 %token	INCLUDE
+%token	INCLUDEOPTIONS
 %token	FILES
 
 %token	<str>	ENVLINE
@@ -86,6 +87,7 @@
 const	char *yyfile;
 struct  file_list_head ftab;
 struct  files_name_head fntab;
+struct	options_files_name_head optfntab;
 char	errbuf[80];
 int	maxusers;
 
@@ -96,6 +98,7 @@
 
 static void newdev(char *name);
 static void newfile(char *name);
+static void newoptionsfile(char *name);
 static void newenvvar(char *name, bool is_file);
 static void rmdev_schedule(struct device_head *dh, char *name);
 static void newopt(struct opt_head *list, char *name, char *value, int append, int dupe);
@@ -138,6 +141,10 @@
 		  	include($2, 0);
 		};
 		|
+	INCLUDEOPTIONS PATH SEMICOLON { newoptionsfile($2); };
+		|
+	INCLUDEOPTIONS ID SEMICOLON { newoptionsfile($2); };
+		|
 	FILES ID SEMICOLON { newfile($2); };
 	        |
 	SEMICOLON
@@ -338,6 +345,21 @@
 	STAILQ_INSERT_TAIL(&fntab, nl, f_next);
 }
 
+/*
+ * Add a new options file to the list of options files.
+ */
+static void
+newoptionsfile(char *name)
+{
+	struct files_name *nl;
+
+	nl = (struct files_name *) calloc(1, sizeof *nl);
+	if (nl == NULL)
+		err(EXIT_FAILURE, "calloc");
+	nl->f_name = name;
+	STAILQ_INSERT_TAIL(&optfntab, nl, f_next);
+}
+
 static void
 newenvvar(char *name, bool is_file)
 {
diff --git a/usr.sbin/config/lang.l b/usr.sbin/config/lang.l
--- a/usr.sbin/config/lang.l
+++ b/usr.sbin/config/lang.l
@@ -83,6 +83,7 @@
 	{ "nooption",	NOOPTION },
 	{ "nooptions",	NOOPTION },
 	{ "include",	INCLUDE },
+	{ "includeoptions", INCLUDEOPTIONS },
 	{ "files", 	FILES },
 	{ 0, 0 },
 };
diff --git a/usr.sbin/config/main.cc b/usr.sbin/config/main.cc
--- a/usr.sbin/config/main.cc
+++ b/usr.sbin/config/main.cc
@@ -92,6 +92,7 @@
 int	debugging;
 int	found_defaults;
 int	incignore;
+int	verbose;
 
 /*
  * Preserve old behaviour in INCLUDE_CONFIG_FILE handling (files are included
@@ -144,7 +145,8 @@
 	STAILQ_INIT(&ftab);
 	STAILQ_INIT(&hints);
 	STAILQ_INIT(&envvars);
-	while ((ch = getopt(argc, argv, "Cd:gI:mps:Vx:")) != -1)
+	STAILQ_INIT(&optfntab);
+	while ((ch = getopt(argc, argv, "Cd:gI:mps:Vvx:")) != -1)
 		switch (ch) {
 		case 'C':
 			filebased = 1;
@@ -179,6 +181,9 @@
 		case 'V':
 			printf("%d\n", CONFIGVERS);
 			exit(0);
+		case 'v':
+			verbose++;
+			break;
 		case 'x':
 			kernfile = optarg;
 			break;
diff --git a/usr.sbin/config/mkoptions.cc b/usr.sbin/config/mkoptions.cc
--- a/usr.sbin/config/mkoptions.cc
+++ b/usr.sbin/config/mkoptions.cc
@@ -46,6 +46,7 @@
 #include <err.h>
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 #include <sys/param.h>
 #include "config.h"
 #include "y.tab.h"
@@ -79,7 +80,9 @@
 	}	
 
 	if (maxusers == 0) {
-		/* fprintf(stderr, "maxusers not specified; will auto-size\n"); */
+		if (verbose)
+			fprintf(stderr,
+			    "maxusers not specified; will auto-size\n");
 	} else if (maxusers < users.u_min) {
 		fprintf(stderr, "minimum of %d maxusers assumed\n",
 		    users.u_min);
@@ -371,8 +374,15 @@
 	char genopt[MAXPATHLEN];
 
 	fp = fopen(fname, "r");
-	if (fp == NULL)
+	if (fp == NULL) {
+		if (verbose) {
+			getcwd(genopt, sizeof(genopt));
+			fprintf(stderr, "Unable to open options file: %s\n",
+			    fname);
+			fprintf(stderr, "CWD: %s\n", genopt);
+		}
 		return (0);
+	}
 	while (!(wd = get_word(fp)).eof()) {
 		if (wd.eol())
 			continue;
@@ -425,6 +435,7 @@
 read_options(void)
 {
 	char fname[MAXPATHLEN];
+	struct files_name *nl, *tnl;
 
 	SLIST_INIT(&otab);
 	read_option_file("../../conf/options", 0);
@@ -434,6 +445,12 @@
 		(void)snprintf(fname, sizeof fname, "options.%s", machinename);
 		read_option_file(fname, 0);
 	}
+	for (nl = STAILQ_FIRST(&optfntab); nl != NULL; nl = tnl) {
+		read_option_file(nl->f_name, 0);
+		tnl = STAILQ_NEXT(nl, f_next);
+		free(nl->f_name);
+		free(nl);
+	}
 	read_option_file("../../conf/options-compat", OL_ALIAS);
 }