vim-patch:8.1.1803: all builtin functions are global

Problem:    All builtin functions are global.
Solution:   Add the method call operator ->.  Implemented for a limited number
            of functions.
ac92e25a33

- Note that to *exactly* port hunk @@ -7376,18 +7444,19 from
  handle_subscript(), we need the :scriptversion patches (I have an open
  PR for those, but this patch works fine without them anyway).
- Port call_internal_func() from v7.4.2058.
- Adjust some error messages in tests, as they rely on the Blob patches.
- Add a modeline to test_method.vim.

Ignore the global_functions and base_method tables and prefer the
current GPerf implementation. Instead, add an extra base_arg field to
VimLFuncDef that holds the number of the argument to use as the base
(1-indexed, so that 0 may be used to refer to functions that cannot be
used as methods).

This also means we support using any argument as a base from the get-go,
rather than just the first (Vim includes this ability in future patches,
however).

To mark a function as usable as a method, use the "base" key as
described in eval.lua.

src/nvim/eval.lua

@@ -5,6 +5,9 @@
 -- args  Number of arguments, list with maximum and minimum number of arguments
 --       or list with a minimum number of arguments only. Defaults to zero
 --       arguments.
+-- base  For methods: the argument to use as the base argument (1-indexed):
+--       base->method()
+--       Defaults to zero (function cannot be used as a method).
 -- func  Name of the C function which implements the VimL function. Defaults to
 --       `f_{funcname}`.
 
@@ -16,7 +19,7 @@ return {
   funcs={
     abs={args=1},
     acos={args=1, func="float_op_wrapper", data="&acos"},  -- WJMc
-    add={args=2},
+    add={args=2, base=1},
     ['and']={args=2},
     api_info={},
     append={args=2},
@@ -73,10 +76,10 @@ return {
     complete_check={},
     complete_info={args={0, 1}},
     confirm={args={1, 4}},
-    copy={args=1},
+    copy={args=1, base=1},
     cos={args=1, func="float_op_wrapper", data="&cos"},
     cosh={args=1, func="float_op_wrapper", data="&cosh"},
-    count={args={2, 4}},
+    count={args={2, 4}, base=1},
     cscope_connection={args={0, 3}},
     ctxget={args={0, 1}},
     ctxpop={},
@@ -93,7 +96,7 @@ return {
     did_filetype={},
     diff_filler={args=1},
     diff_hlID={args=2},
-    empty={args=1},
+    empty={args=1, base=1},
     environ={},
     escape={args=2},
     eval={args=1},
@@ -105,12 +108,12 @@ return {
     exp={args=1, func="float_op_wrapper", data="&exp"},
     expand={args={1, 3}},
     expandcmd={args=1},
-    extend={args={2, 3}},
+    extend={args={2, 3}, base=1},
     feedkeys={args={1, 2}},
     file_readable={args=1, func='f_filereadable'},  -- obsolete
     filereadable={args=1},
     filewritable={args=1},
-    filter={args=2},
+    filter={args=2, base=1},
     finddir={args={1, 3}},
     findfile={args={1, 3}},
     flatten={args={1, 2}},
@@ -128,7 +131,7 @@ return {
     funcref={args={1, 3}},
     ['function']={args={1, 3}},
     garbagecollect={args={0, 1}},
-    get={args={2, 3}},
+    get={args={2, 3}, base=1},
     getbufinfo={args={0, 1}},
     getbufline={args={2, 3}},
     getbufvar={args={2, 3}},
@@ -187,14 +190,14 @@ return {
     hostname={},
     iconv={args=3},
     indent={args=1},
-    index={args={2, 4}},
+    index={args={2, 4}, base=1},
     input={args={1, 3}},
     inputdialog={args={1, 3}},
     inputlist={args=1},
     inputrestore={},
     inputsave={},
     inputsecret={args={1, 2}},
-    insert={args={2, 3}},
+    insert={args={2, 3}, base=1},
     interrupt={args=0},
     invert={args=1},
     isdirectory={args=1},
@@ -202,7 +205,7 @@ return {
     islocked={args=1},
     isnan={args=1},
     id={args=1},
-    items={args=1},
+    items={args=1, base=1},
     jobclose={args={1, 2}, func="f_chanclose"},
     jobpid={args=1},
     jobresize={args=3},
@@ -210,12 +213,12 @@ return {
     jobstart={args={1, 2}},
     jobstop={args=1},
     jobwait={args={1, 2}},
-    join={args={1, 2}},
+    join={args={1, 2}, base=1},
     json_decode={args=1},
     json_encode={args=1},
-    keys={args=1},
+    keys={args=1, base=1},
     last_buffer_nr={},  -- obsolete
-    len={args=1},
+    len={args=1, base=1},
     libcall={args=3},
     libcallnr={args=3},
     line={args={1, 2}},
@@ -226,7 +229,7 @@ return {
     log={args=1, func="float_op_wrapper", data="&log"},
     log10={args=1, func="float_op_wrapper", data="&log10"},
     luaeval={args={1, 2}},
-    map={args=2},
+    map={args=2, base=1},
     maparg={args={1, 4}},
     mapcheck={args={1, 3}},
     match={args={2, 4}},
@@ -238,9 +241,9 @@ return {
     matchlist={args={2, 4}},
     matchstr={args={2, 4}},
     matchstrpos={args={2,4}},
-    max={args=1},
+    max={args=1, base=1},
     menu_get={args={1, 2}},
-    min={args=1},
+    min={args=1, base=1},
     mkdir={args={1, 3}},
     mode={args={0, 1}},
     msgpackdump={args=1},
@@ -270,11 +273,11 @@ return {
     reltime={args={0, 2}},
     reltimefloat={args=1},
     reltimestr={args=1},
-    remove={args={2, 3}},
+    remove={args={2, 3}, base=1},
     rename={args=2},
-    ['repeat']={args=2},
+    ['repeat']={args=2, base=1},
     resolve={args=1},
-    reverse={args=1},
+    reverse={args=1, base=1},
     round={args=1, func="float_op_wrapper", data="&round"},
     rpcnotify={args=varargs(2)},
     rpcrequest={args=varargs(2)},
@@ -327,7 +330,7 @@ return {
     sin={args=1, func="float_op_wrapper", data="&sin"},
     sinh={args=1, func="float_op_wrapper", data="&sinh"},
     sockconnect={args={2,3}},
-    sort={args={1, 3}},
+    sort={args={1, 3}, base=1},
     soundfold={args=1},
     stdioopen={args=1},
     spellbadword={args={0, 1}},
@@ -344,7 +347,7 @@ return {
     strftime={args={1, 2}},
     strgetchar={args={2, 2}},
     stridx={args={2, 3}},
-    string={args=1},
+    string={args=1, base=1},
     strlen={args=1},
     strpart={args={2, 4}},
     strptime={args=2},
@@ -383,11 +386,11 @@ return {
     tr={args=3},
     trim={args={1,3}},
     trunc={args=1, func="float_op_wrapper", data="&trunc"},
-    type={args=1},
+    type={args=1, base=1},
     undofile={args=1},
     undotree={},
-    uniq={args={1, 3}},
-    values={args=1},
+    uniq={args={1, 3}, base=1},
+    values={args=1, base=1},
     virtcol={args=1},
     visualmode={args={0, 1}},
     wait={args={2,3}},