vim-patch:7.4.1893

Problem:    Cannot easily get the window ID for a buffer.
Solution:   Add bufwinid().

b3619a90ea

src/nvim/eval.lua

@@ -45,6 +45,7 @@ return {
     bufloaded={args=1},
     bufname={args=1},
     bufnr={args={1, 2}},
+    bufwinid={args=1},
     bufwinnr={args=1},
     byte2line={args=1},
     byteidx={args=2},