Problem:    Problem with :cd when editing file in non-existent directory. (Yee
            Cheng Chin)
Solution:   Prepend the current directory to get the full path. (closes vim/vim#8903)
https://github.com/vim/vim/commit/c6376c798433bcb9ee38a8664299d11454546950

Problem:    Items in a list given to :const can still be modified.
Solution:   Work like ":lockvar! name" but don't lock referenced items.
            Make locking a blob work.
https://github.com/vim/vim/commit/021bda56710d98c09a6b35610a476ab2dd8c58ad

Problem:    Cannot use octal numbers in scriptversion 4.
Solution:   Add the "0o" notation. (Ken Takata, closes vim/vim#5304)
https://github.com/vim/vim/commit/c17e66c5c0acd5038f1eb3d7b3049b64bb6ea30b

:scriptversion is N/A.

Cherry-pick latest str2nr() doc changes from v8.1.2035.
Cherry-pick various mentions of the 0o prefix from:
 - v8.2.2324
 - https://github.com/vim/vim/commit/2346a6378483c9871016f9fc821ec5cbea638f13
 - https://github.com/vim/vim/commit/11e3c5ba820325b69cb56f70e13c21d7b8808d33
 - https://github.com/vim/vim/commit/82be4849eed0b8fbee45bc8da99b685ec89af59a

Patch used ascii_isbdigit() by mistake, which was fixed in v8.2.2309.

Make STR2NR_OOCT work the same as STR2NR_OCT when forcing.
In Vim, STR2NR_FORCE | STR2NR_OOCT isn't handled, and doesn't actually
force anything. Rather than abort(), make it work as STR2NR_OCT.

This means STR2NR_FORCE | STR2NR_OCT works the same as
STR2NR_FORCE | STR2NR_OOCT and STR2NR_FORCE | STR2NR_OCT | STR2NR_OOCT.

Problem:    The str2nr() tests fail.
Solution:   Add missing part of patch.
https://github.com/vim/vim/commit/1ac90b4fa63414d56750559506a3e076df6923b0

Add extra tests for quoted numbers in vim_str2nr_spec.lua, as the
included ones in this patch are somewhat lacking.

Problem:    Obvious mistakes are accepted as valid expressions.
Solution:   Be more strict about parsing numbers. (Yasuhiro Matsumoto,
            closes vim/vim#3981)
https://github.com/vim/vim/commit/16e9b85113e0b354ece1cb4f5fcc7866850f3685

Update vim_str2nr_spec.lua to add more tests that use strict = true.

Revert "tests: unit: fix preprocess: pass -m32 for 32bit ABI (#11073)"

This reverts commit ed11721b6bb36042ab065b5045c8eb01115b8902.

It broke multiple 32-bit builds and isn't actually required for building
in a true x86 32-bit environment.

Remove syncolor.vim in favor of defining the default highlight groups
directly in `init_highlight`. This approach provides a number of
advantages:

1. The highlights are always defined, regardless of whether or not the
   syntax regex engine is enabled.
2. Redundant sourcing of syntax files is eliminated (syncolor.vim was
   often sourced multiple times based on how the user's colorscheme file
   was written).
3. The syntax highlighting regex engine and the highlight groups
   themselves are more fully decoupled.
4. Removal of the confusing `:syntax on` / `:syntax enable` dichotomy
   (they now both do the same thing).

This approach also correctly solves a number of bugs related to
highlighting (#15176, #12573, #15205).