[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.
gdb tells me it freezes in `win_line() -> next_search_hl() -> ml_get_buf()`. Of these three, only `next_search_hl()` seems to use `rm.regprog`, but it checks if it's `NULL` first, so that shouldn't matter.