sync code with last improvements from OpenBSD

lib/libxcb/libxcb/Makefile

@@ -0,0 +1,51 @@
+#	$OpenBSD: Makefile,v 1.8 2017/10/23 16:50:28 matthieu Exp $
+
+LIB=		xcb
+
+HEADERS=	xcb.h \
+		xcbext.h \
+
+EXTHEADERS=	xproto.h \
+		bigreq.h \
+		xc_misc.h
+
+_SRCDIR=	${LIBXCB}/src
+
+SRCS= \
+	xcb_conn.c \
+	xcb_out.c \
+	xcb_in.c \
+	xcb_ext.c \
+	xcb_xid.c \
+	xcb_list.c \
+	xcb_util.c \
+	xcb_auth.c \
+	xproto.c \
+	bigreq.c \
+	xc_misc.c
+
+PKGCONFIG=	xcb.pc
+
+NEEDED=		xau >= 0.99.2 xdmcp
+
+CFLAGS+=	--std=c99
+
+XCBPROTO_VERSION!=	pkg-config --modversion xcb-proto
+
+EXTRA_PKGCONFIG_SUBST=	'-e s,@NEEDED@,${NEEDED},g' \
+			'-e s,@XCBPROTO_VERSION@,${XCBPROTO_VERSION},g' \
+			    '-e s,@LIBS@,,g' \
+
+LDADD=		`pkg-config --libs "${NEEDED}"`
+
+install-ext:
+	@echo installing ${EXTHEADERS} in ${INCSDIR}/${HEADER_SUBDIR}
+	cd ${.CURDIR}/../src; for i in ${EXTHEADERS}; do \
+	   cmp -s $$i ${DESTDIR}${INCSDIR}/${HEADERS_SUBDIR}$$i || \
+		${INSTALL_DATA} $$i ${DESTDIR}${INCSDIR}/${HEADERS_SUBDIR}$$i;\
+	done
+
+realinstall: install-ext
+
+.include <bsd.lib.mk>
+.include <bsd.xorg.mk>

lib/libxcb/libxcb/shlib_version

@@ -0,0 +1,2 @@
+major=4
+minor=1