diff --git a/tools/build/depend-cleanup.sh b/tools/build/depend-cleanup.sh
--- a/tools/build/depend-cleanup.sh
+++ b/tools/build/depend-cleanup.sh
@@ -116,3 +116,6 @@
 	echo "Removing old zic directory"
 	rm -rf "$OBJTOP"/usr.sbin/zic/zic
 fi
+
+# 20220126  x    move from mkmakefile.c to mkmakefile.cc
+clean_dep   usr.bin/config  mkmakefile c
diff --git a/usr.sbin/config/Makefile b/usr.sbin/config/Makefile
--- a/usr.sbin/config/Makefile
+++ b/usr.sbin/config/Makefile
@@ -3,9 +3,9 @@
 
 SRCDIR:=${.PARSEDIR:tA}
 
-PROG=	config
+PROG_CXX=	config
 MAN=	config.5 config.8
-SRCS=	config.y main.c lang.l mkmakefile.c mkheaders.c \
+SRCS=	config.y main.c lang.l mkmakefile.cc mkheaders.c \
 	mkoptions.c y.tab.h kernconf.c
 
 FILE2C?=file2c
@@ -18,7 +18,7 @@
 
 NO_WMISSING_VARIABLE_DECLARATIONS=
 
-LIBADD=	nv sbuf
+LIBADD=	sbuf
 
 CLEANFILES+=	kernconf.c
 
diff --git a/usr.sbin/config/mkmakefile.c b/usr.sbin/config/mkmakefile.cc
rename from usr.sbin/config/mkmakefile.c
rename to usr.sbin/config/mkmakefile.cc
--- a/usr.sbin/config/mkmakefile.c
+++ b/usr.sbin/config/mkmakefile.cc
@@ -42,6 +42,7 @@
  * the information in the files files and the
  * additional files for the machine being compiled to.
  */
+#include <sys/param.h>
 
 #include <ctype.h>
 #include <err.h>
@@ -49,13 +50,15 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
-#include <sys/cnv.h>
-#include <sys/nv.h>
-#include <sys/param.h>
+#include <string>
+#include <unordered_map>
+
 #include "y.tab.h"
 #include "config.h"
 #include "configvers.h"
 
+typedef std::unordered_map<std::string, std::string>	env_map;
+
 static char *tail(char *);
 static void do_clean(FILE *);
 static void do_rules(FILE *);
@@ -66,8 +69,8 @@
 static void sanitize_envline(char *result, const char *src);
 static bool preprocess(char *line, char *result);
 static void process_into_file(char *line, FILE *ofp);
-static void process_into_nvlist(char *line, nvlist_t *nvl);
-static void dump_nvlist(nvlist_t *nvl, FILE *ofp);
+static void process_into_map(char *line, env_map &emap);
+static void dump_map(env_map &emap, FILE *ofp);
 
 static void errout(const char *fmt, ...)
 {
@@ -267,35 +270,24 @@
 }
 
 static void
-process_into_nvlist(char *line, nvlist_t *nvl)
+process_into_map(char *line, env_map &emap)
 {
 	char result[BUFSIZ], *s;
 
 	if (preprocess(line, result)) {
 		s = strchr(result, '=');
 		*s = '\0';
-		if (nvlist_exists(nvl, result))
-			nvlist_free(nvl, result);
-		nvlist_add_string(nvl, result, s + 1);
+		emap[result] = s + 1;
 	}
 }
 
 static void
-dump_nvlist(nvlist_t *nvl, FILE *ofp)
+dump_map(env_map &emap, FILE *ofp)
 {
-	const char *name;
-	void *cookie;
-
-	if (nvl == NULL)
-		return;
-
-	while (!nvlist_empty(nvl)) {
-		cookie = NULL;
-		name = nvlist_next(nvl, NULL, &cookie);
-		fprintf(ofp, "\"%s=%s\\0\"\n", name,
-		     cnvlist_get_string(cookie));
 
-		cnvlist_free_string(cookie);
+	for (auto iter : emap) {
+		fprintf(ofp, "\"%s=%s\\0\"\n", iter.first.c_str(),
+		    iter.second.c_str());
 	}
 }
 
@@ -306,7 +298,7 @@
 makehints(void)
 {
 	FILE *ifp, *ofp;
-	nvlist_t *nvl;
+	env_map emap;
 	char line[BUFSIZ];
 	struct hint *hint;
 
@@ -324,17 +316,15 @@
 		fprintf(ofp, "int hintmode = %d;\n",
 			!STAILQ_EMPTY(&hints) ? 1 : 0);
 	fprintf(ofp, "char static_hints[] = {\n");
-	nvl = nvlist_create(0);
 	STAILQ_FOREACH(hint, &hints, hint_next) {
 		ifp = fopen(hint->hint_name, "r");
 		if (ifp == NULL)
 			err(1, "%s", hint->hint_name);
 		while (fgets(line, BUFSIZ, ifp) != NULL)
-			process_into_nvlist(line, nvl);
-		dump_nvlist(nvl, ofp);
+			process_into_map(line, emap);
+		dump_map(emap, ofp);
 		fclose(ifp);
 	}
-	nvlist_destroy(nvl);
 	fprintf(ofp, "\"\\0\"\n};\n");
 	fclose(ofp);
 	moveifchanged(path("hints.c.new"), path("hints.c"));
@@ -347,7 +337,7 @@
 makeenv(void)
 {
 	FILE *ifp, *ofp;
-	nvlist_t *nvl;
+	env_map emap;
 	char line[BUFSIZ];
 	struct envvar *envvar;
 
@@ -365,20 +355,18 @@
 		fprintf(ofp, "int envmode = %d;\n",
 			!STAILQ_EMPTY(&envvars) ? 1 : 0);
 	fprintf(ofp, "char static_env[] = {\n");
-	nvl = nvlist_create(0);
 	STAILQ_FOREACH(envvar, &envvars, envvar_next) {
 		if (envvar->env_is_file) {
 			ifp = fopen(envvar->env_str, "r");
 			if (ifp == NULL)
 				err(1, "%s", envvar->env_str);
 			while (fgets(line, BUFSIZ, ifp) != NULL)
-				process_into_nvlist(line, nvl);
-			dump_nvlist(nvl, ofp);
+				process_into_map(line, emap);
+			dump_map(emap, ofp);
 			fclose(ifp);
 		} else
 			process_into_file(envvar->env_str, ofp);
 	}
-	nvlist_destroy(nvl);
 	fprintf(ofp, "\"\\0\"\n};\n");
 	fclose(ofp);
 	moveifchanged(path("env.c.new"), path("env.c"));