contrib: x265: fix static linking with pkg-config (fixes #16389)

contrib/src/x265/rules.mak

@@ -28,6 +28,9 @@ x265: x265-$(X265_VERSION).tar.bz2 .sum-x265
 	$(BZCAT) "$<" | (cd $@-$(X265_VERSION) && tar xv --strip-components=1)
 	$(APPLY) $(SRC)/x265/x265-ldl-linking.patch
 	$(call pkg_static,"source/x265.pc.in")
+ifndef HAVE_WIN32
+	$(APPLY) $(SRC)/x265/x265-pkg-libs.patch
+endif
 	$(MOVE)
 
 .x265: x265 toolchain.cmake

contrib/src/x265/x265-pkg-libs.patch

+diff -Nru x265.orig/source/x265.pc.in x265/source/x265.pc.in
+--- x265.orig/source/x265.pc.in	2016-08-06 17:04:25.925985965 +0300
++++ x265/source/x265.pc.in	2016-08-06 17:07:06.548987568 +0300
+@@ -7,5 +7,5 @@
+ Description: H.265/HEVC video encoder
+ Version: @X265_LATEST_TAG@
+ Cflags: -I${includedir}
+-Libs:  -L${libdir} -lx265  @PRIVATE_LIBS@
++Libs:  -L${libdir} -lx265  @PRIVATE_LIBS@ -ldl -lpthread
+ Requires: