src: fix potential macro confusion in cmake unity builds

Sources used `lib/curlx.h` with both `ENABLE_CURLX_PRINTF` set and unset
before including it.

In a cmake "unity" batch w

src: fix potential macro confusion in cmake unity builds

Sources used `lib/curlx.h` with both `ENABLE_CURLX_PRINTF` set and unset
before including it.

In a cmake "unity" batch where the first included source had it unset,
the next sources did not get the macros requested with
`ENABLE_CURLX_PRINTF` because `lib/curl.x` had already been included
without them.

Fix it by by making the macros enabled permanently and globally for
internal sources, and dropping `ENABLE_CURLX_PRINTF`.

This came up while testing unity builds with smaller batches. The full,
default unity build where all `src` is bundled up in a single unit, was
not affected.

Fixes:
```
$ cmake -B build -DCMAKE_UNITY_BUILD=ON -DCMAKE_UNITY_BUILD_BATCH_SIZE=15
$ make -C build
...
curl/src/tool_getparam.c: In function ‘getparameter’:
curl/src/tool_getparam.c:2409:11: error: implicit declaration of function ‘msnprintf’; did you mean ‘vsnprintf’? [-Wimplicit-function-declaration]
2409 | msnprintf(buffer, sizeof(buffer), "%" CURL_FORMAT_CURL_OFF_T "-",
| ^~~~~~~~~
| vsnprintf
curl/src/tool_getparam.c:2409:11: warning: nested extern declaration of ‘msnprintf’ [-Wnested-externs]
[...]
```

Reported-by: Daniel Stenberg
Bug: https://github.com/curl/curl/pull/14626#issuecomment-2301663491

Closes #14632

show more ...

copyright: update all copyright lines and remove year ranges

- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- save

copyright: update all copyright lines and remove year ranges

- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- saves us from pointless churn
- git keeps history for us
- the year range is kept in COPYING

checksrc is updated to allow non-year using copyright statements

Closes #10205

show more ...

copyright: make repository REUSE compliant

Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the

copyright: make repository REUSE compliant

Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the file
`.reuse/dep5`.

This commit also adds a Github workflow to check pull requests and adapts
copyright.pl to the changes.

Closes #8869

show more ...

hash: lazy-alloc the table in Curl_hash_add()

This makes Curl_hash_init() infallible which saves error paths.

Closes #8132

curl.se: new home

Closes #6172

hash: make it 'struct Curl_hash'

As internal global names should use captical C.

Closes #5906

checksrc: white space edits to comply to stricter checksrc

code: style updates

unit: make unit test source code checksrc compliant

URLs: change all http:// URLs to https://

unit1602: Fixed failure in torture test

hostip: fix unintended destruction of hash table

.. and added unit1602 for hash.c