Index: sys/conf/files
===================================================================
--- sys/conf/files
+++ sys/conf/files
@@ -11,12 +11,12 @@
 	clean		"acpi_quirks.h"
 bhnd_nvram_map.h		optional bhndbus | bhnd			   \
 	dependency	"$S/dev/bhnd/tools/nvram_map_gen.sh $S/dev/bhnd/tools/nvram_map_gen.awk $S/dev/bhnd/nvram/nvram_map" \
-	compile-with	"$S/dev/bhnd/tools/nvram_map_gen.sh $S/dev/bhnd/nvram/nvram_map -h" \
+	compile-with	"sh $S/dev/bhnd/tools/nvram_map_gen.sh $S/dev/bhnd/nvram/nvram_map -h" \
 	no-obj no-implicit-rule before-depend				   \
 	clean		"bhnd_nvram_map.h"
 bhnd_nvram_map_data.h		optional bhndbus | bhnd			   \
 	dependency	"$S/dev/bhnd/tools/nvram_map_gen.sh $S/dev/bhnd/tools/nvram_map_gen.awk $S/dev/bhnd/nvram/nvram_map" \
-	compile-with	"$S/dev/bhnd/tools/nvram_map_gen.sh $S/dev/bhnd/nvram/nvram_map -d" \
+	compile-with	"sh $S/dev/bhnd/tools/nvram_map_gen.sh $S/dev/bhnd/nvram/nvram_map -d" \
 	no-obj no-implicit-rule before-depend				   \
 	clean		"bhnd_nvram_map_data.h"
 #
Index: sys/conf/kmod.mk
===================================================================
--- sys/conf/kmod.mk
+++ sys/conf/kmod.mk
@@ -417,7 +417,7 @@
     ${SYSDIR}/dev/bhnd/tools/nvram_map_gen.sh \
     ${SYSDIR}/dev/bhnd/nvram/nvram_map
 bhnd_nvram_map.h:
-	${SYSDIR}/dev/bhnd/tools/nvram_map_gen.sh \
+	sh ${SYSDIR}/dev/bhnd/tools/nvram_map_gen.sh \
 	    ${SYSDIR}/dev/bhnd/nvram/nvram_map -h
 .endif
 
@@ -427,7 +427,7 @@
     ${SYSDIR}/dev/bhnd/tools/nvram_map_gen.sh \
     ${SYSDIR}/dev/bhnd/nvram/nvram_map
 bhnd_nvram_map_data.h:
-	${SYSDIR}/dev/bhnd/tools/nvram_map_gen.sh \
+	sh ${SYSDIR}/dev/bhnd/tools/nvram_map_gen.sh \
 	    ${SYSDIR}/dev/bhnd/nvram/nvram_map -d
 .endif
 
Index: sys/dev/bhnd/tools/nvram_map_gen.sh
===================================================================
--- sys/dev/bhnd/tools/nvram_map_gen.sh
+++ sys/dev/bhnd/tools/nvram_map_gen.sh
@@ -7,6 +7,10 @@
 
 BHND_TOOLDIR="$(dirname $0)/"
 
+if [ -z "$AWK" ]; then
+    AWK=/usr/bin/awk
+fi
+
 LC_ALL=C; export LC_ALL
 
-"$BHND_TOOLDIR/nvram_map_gen.awk" $@
+"$AWK" -f "$BHND_TOOLDIR/nvram_map_gen.awk" $@