shadowsocksr-libev: Upgrade PCRE2 & drop libopenssl-legacy depends

* shadowsocksr-libev: Upgrade PCRE to PCRE2

shadowsocksr-libev/src/server/Makefile.in

@@ -105,7 +105,7 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltoptions.m4 \
 	$(top_srcdir)/m4/ltsugar.m4 $(top_srcdir)/m4/ltversion.m4 \
 	$(top_srcdir)/m4/lt~obsolete.m4 $(top_srcdir)/m4/mbedtls.m4 \
-	$(top_srcdir)/m4/openssl.m4 $(top_srcdir)/m4/pcre.m4 \
+	$(top_srcdir)/m4/openssl.m4 $(top_srcdir)/m4/pcre2.m4 \
 	$(top_srcdir)/m4/polarssl.m4 \
 	$(top_srcdir)/m4/stack-protector.m4 $(top_srcdir)/m4/zlib.m4 \
 	$(top_srcdir)/libev/libev.m4 $(top_srcdir)/configure.ac