[WIP] Add matchaddpos()-related vim patches. [vim-patch: 7.4.330, 7.4.334, 7.4.344, 7.4.362]

Adds patches 7.4.330, 334, 344 and 362.

WARNING: The build passes, but the created executable is unresponsive, for some reason. The error seems to be caused by something in patch 7.4.330. Some help would be appreciated.
That was when I was opening a totally blank file. Opening a small file, moving the cursor between two parens `(|)` and hitting `A` to enter insert mode and suddenly I get a segfault from `win_update(wp=0x...) -> re_multiline(prog=0x1)`. Apparently, testing for `NULL` won't cut it!