lib: hook libder up to the build

libder will be used in upcoming ECC support in the pkg(7) bootstrap to
read DER-encoded keys and signatures.

(cherry picked from commit f59bb61e1eb4d1e4fc3c60cc14779d0668267cb2)

lib/Makefile

@@ -17,6 +17,7 @@ SUBDIR_BOOTSTRAP= \
 	libc++ \
 	libc++experimental \
 	libcxxrt \
+	libder \
 	libelf \
 	libssp \
 	libssp_nonshared \

lib/libder/Makefile

@@ -0,0 +1,13 @@
+
+LIB=	der
+INTERNALLIB=
+
+.PATH:	${SRCTOP}/contrib/libder/libder
+SRCS+=	libder.c \
+	libder_error.c \
+	libder_obj.c \
+	libder_read.c \
+	libder_type.c \
+	libder_write.c
+
+.include <bsd.lib.mk>

share/mk/src.libnames.mk

@@ -43,6 +43,7 @@ _INTERNALLIBS=	\
 		bsnmptools \
 		c_nossp_pic \
 		cron \
+		der \
 		elftc \
 		fdt \
 		fifolog \
@@ -586,6 +587,9 @@ LIBTELNET?=	${LIBTELNETDIR}/libtelnet${PIE_SUFFIX}.a
 LIBCRONDIR=	${_LIB_OBJTOP}/usr.sbin/cron/lib
 LIBCRON?=	${LIBCRONDIR}/libcron${PIE_SUFFIX}.a
 
+LIBDERDIR=	${_LIB_OBJTOP}/lib/libder
+LIBDER?=	${LIBDERDIR}/libder${PIE_SUFFIX}.a
+
 LIBNTPDIR=	${_LIB_OBJTOP}/usr.sbin/ntp/libntp
 LIBNTP?=	${LIBNTPDIR}/libntp${PIE_SUFFIX}.a