By making them defaults, then fixing and/or reshuffling remaining
exceptions as necessary.
- checksrc: ban by default: `snprintf`, `vsnprintf`, `sscanf`, `strtol`.
- examples: replace `strtol` with `atoi` to avoid a checksrc exception.
- tests/libtest: replace `strtol` with `atol`.
- tests/server: replace most `strtol` with `atol`.
- tests/server: replace most `strtoul` with `atol`/`atoi`.
- tests/server: drop no longer used `util_ultous`.
- fix typo in checksrc rules: `vsnprint` -> `vsnprintf`.
- update local exceptions.
Also:
- examples: ban curl printf functions. They're discouraged in user code.
- examples: replace curl printf with system printf.
Add `snprintf` workaround for <VS2015.
- examples/synctime: fix `-Wfloat-equal`.
- examples/synctime: exclude for non-Windows and non-UWP Windows.
- examples/synctime: build by default.
Closes#18823
To avoid hitting `-Wreserved-macro-identifier` where possible.
- amigaos: introduce local macro instead of reusing `__request()`.
- easy_lock: avoid redefining `__has_builtin()`.
Follow-up to 33fd57b8ff#9062
- rand: drop interim macro `_random()`.
- windows: rename local macro `_tcsdup()` to `Curl_tcsdup()`.
To avoid using the reserved macro namespace and to avoid
colliding with `_tcsdup()` as defined by Windows headers.
- checksrc: ban `_tcsdup()` in favor of `Curl_tcsdup()`.
- tool_doswin: avoid redefining `_use_lfn()` (MS-DOS).
- tool_findfile: limit `__NO_NET_API` hack to AmigaOS.
Syncing this pattern with `lib/netrc.c`.
Follow-up to 784a8ec2c1#16279
- examples/http2-upload: avoid reserved namespace for local macro.
More cases will be removed when dropping WinCE support via #17927.
Cases remain when defining external macros out of curl's control.
Ref: #18477Closes#18482
