Backtrack on previous change that aimed to solve the wrong `share.h`
being included. It turns out it did not fix this issue. At the same time
it introduced relative header filenames and the need to include the same
headers differently depending on the source files' location, reducing
readability and editability.
Replace this method by re-adding curl's lib source directory to the
header path and addressing headers by the their full, relative name to
that base directory. Aligning with this method already used in src and
tests.
With these advantages:
- makes includes easier to read, recognize, grep, sort, write, and copy
between sources,
- syncs the way these headers are included across curl components,
- avoids the ambiguity between system `schannel.h`, `rustls.h` vs.
local headers using the same names in `lib/vtls`,
- silences clang-tidy `readability-duplicate-include` checker, which
detects the above issue,
Ref: https://clang.llvm.org/extra/clang-tidy/checks/readability/duplicate-include.html
- possibly silences TIOBE coding standard warnings:
`6.10.2.a: Don't use relative paths in #include statements.`
- long shot: it works well with concatenated test sources, for
clang-tidy-friendly custom unity builds. Ref: #20667
Slight downside: it's not enforced.
If there happens to be a collision between a local `lib/*.h` header and
a system one, the solution is to rename (possibly with its `.c`
counterpart) into the `curl_` namespace. This is also the method used by
curl in the past.
Also:
- curlx/inet_pton: reduce scope of an include.
- toolx/tool_time: apply this to an include, and update VS project
files accordingly. Also dropping unnecessary lib/curlx header path.
- clang-tidy: enable `readability-duplicate-include`.
Follow-up to 3887069c66#19676
Follow-up to 625f2c1644#16991#16949Closes#20623
Stop detecting this function and drop the local fallback.
Let us know if this update is causing an issue.
Notes:
- on Windows `_strdup()` is required instead.
- `strdup()/_strdup()` were required before this patch to build one of
the examples: `block_ip`.
- `strdup()/_strdup()` were required in 8.18.0 and earlier to build
tests.
Closes#20505
- de-dupe lib/src strdup/memdup functions into curlx.
- introduce `CURLX_STRDUP_LOW()` for mapping `strdup()`, and to do it at
one place within the code, in `curl_setup.h`.
- tests/server: use `curlx_strdup()`. (Also to fix building without
a system `strdup()`.)
- curlx/curlx.h: shorten and tidy up.
- adjust Windows build path to not need `HAVE_STRDUP`.
- build: stop detecting `HAVE_STRDUP` on Windows.
Closes#20497
