libtins: Update to 4.2

Added size optimizations.

Added explicit options to make sure Boost doesn't get included.

Several Makefile cleanups.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

libs/libtins/patches/010-pkgconfig.patch

@@ -0,0 +1,10 @@
+--- a/libtins.pc.in
++++ b/libtins.pc.in
+@@ -1,6 +1,6 @@
+ prefix=@pkgconfig_prefix@
+ exec_prefix=@pkgconfig_exec_prefix@
+-libdir=@pkgconfig_libdir@
++libdir=${exec_prefix}/lib
+ includedir=${prefix}/include
+ 
+ Name: libtins