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.

Differential Revision:	https://reviews.freebsd.org/D48116

lib/Makefile

@@ -15,6 +15,7 @@ SUBDIR_BOOTSTRAP= \
 	libc++ \
 	libc++experimental \
 	libcxxrt \
+	libder \
 	libdiff \
 	libelf \
 	libssp \

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

@@ -44,6 +44,7 @@ _INTERNALLIBS=	\
 		bsnmptools \
 		c_nossp_pic \
 		cron \
+		der \
 		diff \
 		elftc \
 		fdt \
@@ -614,6 +615,9 @@ 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