Fix `HAVE_GETHOSTBYNAME_R_*` feature detections always failing with
`CURL_WERROR=ON` due to stripping a const.
Also fix the GHA/cmake-vs-configure to enable `CURL_WERROR=ON` to sync
this setting with `./configure` which enables it by default. With that,
CI detects this issue.
```
CMake/CurlTests.c:73:19: error: initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
73 | char *address = "example.com";
| ^~~~~~~~~~~~~
```
Ref: https://github.com/curl/curl/actions/runs/13225827821/job/36916564107#step:33:4198Closes#16282
Add CMake test project consuming curl via these methods:
`FetchContent`, `add_subdirectory()`, `find_package()`.
Also:
- GHA/distcheck: run these tests in CI.
- cmakelint: exclude a warning for calling "wonky-cased" built-in
CMake functions, such as `FetchContent_Declare()`.
Closes#16126
For Find modules where `<Modulename>` is not fully uppercase.
`<Modulename>` is case-exact name used in the Find modules filename:
`CMake/Find<Moduleame>.cmake`.
`find_package_handle_standard_args()` sets both `<MODULENAME>_FOUND` and
`<Modulename>_FOUND` when detecting the dependency. Some CMake code
relies on this and 3rd-party code may rely on it too. Make sure to set
the latter variant when detecting the dependency via `pkg-config`, where
we don't call `find_package_handle_standard_args()`.
CMake sets these variable to `TRUE` (not `ON` or `1`). Replicate this
for compatibility.
Closes#16153
We don't pursue this, and the necessary `#pragma` got in the way of
compiling curl with gcc 4.2 and older. Drop the logic completely.
Follow-up to 8a266ac488#15939
Reported-by: prpr19xx on Github
Fixes#16152Closes#16157
- add `iphlpapi` library for c-ares.
Ref: 082d98ba6b
- fix to not add system libs if the dependency was not found.
librtmp, Rustls, wolfSSL
Follow-up to 421e592db2#15832
Follow-up to 7bab201abe#15193Closes#16089
This variable was meant to be used by curl Find modules, but it turns
out it makes no sense to use those from `curl-config.cmake.in`. It means
this variable was not used before and will not be used in the future,
and therefore safe to delete.
Also add missing macros passed to `curl-config.cmake` to comment.
Ref: https://github.com/curl/curl/pull/14930#discussion_r1929537797Closes#16087
- silence false positive picky warnings.
- avoid "possible noreturn" warnings for standalone tests and examples.
- fix to compile without `#pragma GCC diagnostic push` support.
- fix "#pragma GCC diagnostic not allowed inside functions".
Prerequisite for #15975 that needs GCC 4.4 for the latest pre-built
CeGCC/mingw32ce toolchain for Windows CE.
Cherry-picked from #15975Closes#16062
They play better with Unixy shells. The compiler has been supporting
dash options since its early versions.
Also fix to detect warnings options passed in dash-style.
Closes#16063
iOS:
- add jobs with autotools, CMake, CMake Xcode generator.
The Xcode generator is >10x slower than Unix Makefiles. Keep it
because it's the one recommended by CMake and for having its own
quirks we may want to know about.
- build, cache and use LibreSSL for these jobs.
With workaround for an iOS build issue fixed in master.
- make Xcode generator work by explicitly disabling code signing.
- make tests and examples build with the Xcode generator by setting
`-DMACOSX_BUNDLE_GUI_IDENTIFIER=se.curl`, to avoid
"Bundle identifier is missing" errors.
- cmake: disable `CURL_USE_PKGCONFIG` by default for Apple device.
- cmake: add `stdc++` library for BoringSSL and AWS-LC, with
`OPENSSL_USE_STATIC_LIBS=ON` set.
- cmake: add workaround for Xcode generator issue, where it cannot
handle two targets depending on one custom command. A better fix may
be dropping `tool_hugehelp.c` and `tool_ca_embed.c` from curltool
library. For a future PR.
Android:
- add vcpkg to Android jobs, enable dependencies.
Assisted-by: Tal Regev via #16045
- make vcpkg work with autotools.
- pass `--with-brotli` to autotools to detect the vcpkg-supplied brotli.
- enable BoringSSL for Android and add a job with it.
- silence 457 CMake configure warnings about the Android NDK CMake
scripts targeting freshly deprecated CMake versions.
These were much more involved than imagined. Basically nothing works out
of the box, and when combined, everything becomes a unique edge case.
autotools builds were a much easier to make work than CMake ones.
Also:
- GHA/non-native: re-sync names to be shorter and more aligned with
other workflows.
- GHA: add `persist-credentials: false` where missing.
Unresolved issues:
- `OPENSSL_ROOT_DIR` ignored/mis-used when pointing it to LibreSSL.
CMake seems to prepend the sysroot to the passed absolute directory.
Found no workaround.
- CMake when combined with Android, both the Google-recommended method
and the built-in CMake method fail to provide a way to avoid
`pkg-config` packages at system directories. Failed to find a knob
that can remove `/usr/include` from the search path. The workaround is
to disable zstd. (I enabled it by default in this release, maybe
premature?: f2adb3b6d7#15431)
Disabling `pkg-config` doesn't work because vcpkg dependencies do not
link without it.
- CMake's Xcode generator is slow because each `try_compile()` feature
check springs a new CMake + Xcode project taking a long time to run,
just to compile single-liner C files. A known issue, with no solution.
`-DCMAKE_MACOSX_BUNDLE=OFF` did not help, limiting build types to
a single one (e.g. `Debug`) also had no effect.
make | Xcode | GHA run
:---- | :---- | :--------------------------------------------------------------------
16s | 2m57s | https://github.com/curl/curl/actions/runs/12866334102/job/35868712426
23s | 4m13s | https://github.com/curl/curl/actions/runs/12868128013/job/35874212461
16s | 3m39s | https://github.com/curl/curl/actions/runs/12859073531/job/35849041880
14s | 2m23s | https://github.com/curl/curl/actions/runs/12858298423/job/35847201313
15s | 2m36s | https://github.com/curl/curl/actions/runs/12858058492/job/35846669761
19s | 3m19s | https://github.com/curl/curl/actions/runs/12868919430/job/35876601168Closes#16043
On Windows a successful `sched_yield()` detection requires mingw-w64
built with POSIX threads (not Win32 threads) and GCC (not llvm/clang).
(linking to `winpthread` via custom options may also work.)
In CMake builds, it was pre-cached as unavailable before this patch.
When detected (via autotools), it got only used for Windows XP or older
targets combined with a non-GCC, non-clang compiler that doesn't support
`__builtin_ia32_pause()`, or with the Intel C compiler. According to
`lib/easy_lock.h`.
mingw-w64 only supports GCC and clang, leaving a very narrow chance when
`shed_yield()` gets called on Windows. Even then, `sched_yield()` is
implemented in `winpthread` as `Sleep(0)`, which may or not be a useful.
It's also trivial to implement locally if it is, and such rare build
combination is also deemed useful.
Thus, this patch marks `sched_yields()` permanently unavailable on the
Windows platform also with autotools, and instead of pre-caching, skip
this feature check with CMake.
This syncs `HAVE_SCHED_YIELDS` between builds methods on Windows.
Follow-up to 9b517c8b69#11973
Follow-up to 23af112f55#8680Closes#16037
Replace `strtok_r()` detection with detection mingw-w64 version.
The use this version to pre-fill `HAVE_STRTOK_R`.
This gives use mingw-w64 version information for free.
Closes#16022
`stdatomic.h` and `_Atomic` were first available in gcc 4.9.0 and
llvm/clang 3.6. Set detection values accordingly and save these two
detections on configure runs.
Closes#16036
- GHA/non-native: add Android builds, both cmake and autotools,
both NDK 21 (oldest available) and 35 (newest available)
https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2404-Readme.md
It comes with a maintenance burden to bump the oldest/latest values
with CI runner updates.
- cmake: disable `CURL_USE_PKGCONFIG` by default for Android.
To avoid picking up system package by default.
- build: add `ANDROID-<NDK-LEVEL>` flag to `buildinfo.txt`.
Also detect NDK level with the CMake built-in build method:
https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html#cross-compiling-for-android
- INSTALL.md: add CMake build instructions for Android.
- INSTALL.md: make NDK levels consistent in `./configure` example.
Closes#16014
We decided last year not to pursue avoiding this warning, because it
adds noise and friction, while in most cases not revealing actual code
issues. We fixed the interesting portion of them throughout mid-2024.
Conclude this effort by deleting related FIXMEs and temporary comments.
Follow-up to 3829759bd0#12489Closes#15939
Via these variables, as lists:
- `CURL_SUPPORTED_PROTOCOLS`
- `CURL_SUPPORTED_FEATURES`
As individual flags:
- `CURL_SUPPORTS_<protocol/feature>` = `TRUE`
Also:
- set `CURL_VERSION_STRING` which was missing when using
`find_package(CURL CONFIG)` or
`find_package(CURL NO_MODULE)`.
- set `CURL_<prototol/feature>_FOUND` for compatibility.
- show full list of missing but required `COMPONENTS`.
Assisted-by: Derek Huang
Fixes#15854Closes#15858
We already avoid system framework paths while looking for LDAP headers
to avoid issues.
Do the same while looking for LDAP libraries. This makes sure to find
the regular ldap library (`libldap.tbd`) instead of picking up
`ldap.framework` and let that seep into `libcurl.pc` with a full path.
This makes LDAP detection work on Apple as before introducing FindLDAP.
Follow-up to 49f2a23d50#15273Closes#15895
via `DL_LIBRARY`, `MATH_LIBRARY`, `PTHREAD_LIBRARY` variables.
They are used in Rustls, wolfSSL Find modules.
Also:
- always use `NAMES` keyword in `find_library()` calls.
- respect `find_library()` results for `dl`, `m`, `pthread`.
- formatting.
Closes#15892
- cmake: add auto-detection. Sync this with autotools.
- enable for MS-DOS and AmigaOS builds.
(auto-detection doesn't work for cross-builds.)
- tidy up detection snippet.
- fix comment.
Closes#15868
The new detection method also allows to enable librtmp without using
OpenSSL as a curl TLS backend at the same time.
Also:
- implement manual version detection for librtmp.
Version info is in hex. With CMake 3.13 and newer, extract it as a hex
number. With earlier CMake version, just strip the leading zeroes.
Doing more here seems overkill because librtmp has been standing
at 2.3/2.4 for a decade now. Bumping into hex digits seems unlikely
before deprecating CMake 3.13 support.
librtmp advertises v2.4 via its `pkg-config` module, and v2.3 via
its public header. The latter shows up in `curl -V` and either can
be shown at configure-time depending on detection method.
This isn't a curl bug.
- GHA/macos: enable rtmp in a job.
- apply the "half-detection" fix to the Find module.
`librtmp` is also affected (in CI too), because it depends on libssl and
libcrypto.
Closes#15832
Make the Find modules set and return their respective `pkg-config`
module name(s) to the CMake build process, which then adds those
to the `Requires:` list.
Before this patch, `pkg-config` module names were maintainted in two
separate places. After this patch, they are maintained in the Find
modules for dependencies that have one (most do).
Re-align existing modules with this change: msh3, mbedtls, rustls.
These modules return their `pkg-config` module name only when
detected via `pkg-config`.
Follow-up to d511ec8b0a#15573Closes#15800
Same issue as seen before with libssh2: `libpsl`'s pkg-config module
depends on another module, but that's not found. CMake ends up reporting
`LIBPSL_FOUND=YES`, while leaving `LIBPSL_INCLUDE_DIRS` empty. Then
the build fails to find `psl.h`.
The missing dependency in this case is `icu4c`, which is "keg-only",
meaning it's not exposed in the default Homebrew header, pkg-config,
lib, etc locations. It must be added to the `PKG_CONFIG_PATH` env, as
suggested by the warnings messages of `pkgconf`.
To avoid this fallout, let's ensure that `LIBPSL_INCLUDE_DIRS` is
non-empty when detecting via `pkg-config` and fall back to the CMake
detection method otherwise.
This was an issue till Homebrew libpsl 0.21.5_1, fixed in 0.21.5_2, that
no longer depends on `icu4c`.
Example log:
```
-- Checking for module 'libpsl'
-- Found libpsl, version 0.21.5
Package icu-uc was not found in the pkg-config search path.
Perhaps you should add the directory containing `icu-uc.pc'
to the PKG_CONFIG_PATH environment variable
Package 'icu-uc', required by 'libpsl', not found
[...]
-- Found Libpsl (via pkg-config): (found version "0.21.5")
[...]
In file included from curl/_bld/lib/CMakeFiles/libcurl_static.dir/Unity/unity_0_c.c:4:
In file included from curl/lib/altsvc.c:32:
In file included from curl/lib/urldata.h:145:
curl/lib/psl.h:28:10: fatal error: 'libpsl.h' file not found
^~~~~~~~~~
1 error generated.
```
Follow-up to 39c741b7b0#15408Closes#15827
To avoid this in certain debug build cases:
```
./lib/easy_lock.h:72:20: error: inlining failed in call to 'curl_simple_lock_lock': function not considered for inlining [-Werror=inline]
```
Ref: #13596
Reported-by: Rudi Heitbaum
Fixes#15815Closes#15819
Add `CURL_STRICMP()` macro that works on all platforms depending on
which lib C function is available.
Make sure to always use `_stricmp()` on Windows, which is the
non-deprecated, official API for this on this platform. Before this
patch it used a MinGW-specific call, or a deprecated compatibility
wrapper with MSVC.
Drop `stricmp` variant detections on Windows with autotools.
https://learn.microsoft.com/cpp/c-runtime-library/reference/stricmp-wcsicmp-mbsicmp-stricmp-l-wcsicmp-l-mbsicmp-l
Ref: #15652Closes#15788
- make `curl_dependency_option()` more generic.
- extend `CURL_BROTLI` and `CURL_ZSTD` options to accept
`AUTO` in addition to existing `ON` and `OFF`.
- change `CURL_BROTLI` and `CURL_ZSTD` option default
to `AUTO`. Was: `OFF`.
It brings cmake behavior closer to `./configure`.
Still different:
- `./configure` defaults to `off` which means to check default
locations. cmake checks more locations by default.
(Also tried `NO_CMAKE_PATH`, but then it checked less locations.)
- cmake returns both `brotlicommon` and `brotlidec` libs,
while `./configure` only returns the latter.
- ci: drop explicit cmake options, that are now unnecessary.
- GHA/configure-vs-cmake: make adjustments to make tests pass.
Closes#15431
This reverts commit 39c06f7883#15005.
Combined with most Find modules now supporting `pkg-config`
(39c741b7b0#15408) this change made
mingw-cross builds fragile by picking up OS-native components. Also
adding `/usr/include` to the header path, confusing feature detection.
brotli, c-ares, libpsl, libssh2, nghttp2, nghttp3, ntgcp2, zstd.
Also:
Add workaround for CMake reporting successful libssh2 detection, but
leaving the header directory empty, and causing `libssh2.h` not found
while compiling. It happens when `pkgconf` is not detecting libssh2
dependency libcrypto in Homebrew after `brew unlink openssl` (as in
GHA/macos). The workaround is to require a non-empty header directory
to consider the detection successful. This workaround may need to be
tweaked and/or applied to other Find modules.
Follow-up to 7bab201abe#15193Closes#15408
`Makefile.mk` supported MS-DOS and Amiga, but `./configure` also
supported them in a better tested and more flexible way.
This patch also adds CMake support for MS-DOS/DJGPP and Amiga OS 3.
`Makefile.mk` was not maintained. Delete it in favour of first-tier
build methods.
Also include some non-MS-DOS/AmigaOS-specific tidy-up, see details at
the end of this message.
Details:
- fix/silence all MS-DOS/DJGPP build warnings and issues.
- add MS-DOS support to cmake.
- default to `ENABLE_THREADED_RESOLVER=OFF` for MS-DOS.
- add support for `WATT_ROOT`.
- use static libcurl with MS-DOS.
- fixup default CMake suffixes/prefixes for DJGPP.
- disable hidden symbols for MS-DOS. Not supported on MS-DOS.
- opt-in MS-DOS into `USE_UNIX_SOCKETS`.
- improve MS-DOS support in autotools.
- default to `--disable-threaded-resolver` for MS-DOS.
- make sure to use `close_s()` (from Watt-32) with autotools and cmake.
`Makefile.mk` used it before this patch.
- GHA: add DJGPP cmake (~30s) and autotools (~60s) build jobs.
Also build tests and examples with cmake.
- improve AmigaOS support in autotools:
- configure: detect `CloseSocket()` when it's a macro.
- configure: fix `IoctlSocket` detection on AmigaOS.
- curl-amissl.m4: pass AmiSSL libs to tests/servers.
- add AmigaOS3 support to cmake:
- cmake: fix `HAVE_IOCTLSOCKET_CAMEL` and
`HAVE_IOCTLSOCKET_CAMEL_FIONBIO` detections.
- set necessary system libs.
- add AmiSSL support.
- inet_ntop, inet_pton: fix using it for AmigaOS. cmake detects them,
and they did not compile with AmigaOS.
- cmake: better sync `gethostname` detection with autotools.
Fixes detection for AmigaOS, where `gethostname` is a macro.
- cmake: fix `sys/utime.h` detection on AmigaOS.
- cmake: force-disable `getaddrinfo` for AmigaOS.
- cmake: tweak threading and static/shared default for AmigaOS.
- cmake: rely on manual variable `AMIGA` to enable the platform.
- GHA: add AmigaOS cmake and autotools (~45s) jobs.
Also build tests and examples with cmake.
- INSTALL: update MS-DOS and AmigaOS build instructions.
- amigaos: fix `-Wpointer-sign` and
`zero or negative size array '_args'` in `Printf()`.
- amigaos: fix `-Wpointer-sign`
- amigaos: fix `-Wredundant-decls` `errno` and `h_errno`.
- amigaos: brute-force silence `lseek()` size warnings.
- amigaos: server/resolve: silence `-Wdiscarded-qualifiers`.
- amigaos: server/resolve: fix `-Wpointer-sign`.
- amigaos: fix `CURL_SA_FAMILY_T` type.
- nonblock: prefer `HAVE_IOCTLSOCKET_CAMEL_FIONBIO` for AmigaOS.
`ioctl` is also detected, but fails when used. Make the above override
it for a successful build.
Authored-by: Darren Banfi
Fixes#15537Closes#15603
- tftpd: prefer `HAVE_IOCTLSOCKET_CAMEL_FIONBIO` for AmigaOS.
- tftpd: tidy-up conditional code.
- curl: set stack size to 16384 for AmigaOS3/4
Overriding the default 4096.
Suggested-by: Darren Banfi
Ref: https://github.com/curl/curl/pull/15543#issuecomment-2498783123
Ref: https://wiki.amigaos.net/wiki/Controlling_Application_Stack
- functypes.h: fix `SEND_QUAL_ARG2` for AmigaOS.
- tftp: add missing cast in sendto() call for AmigaOS.
- getinfo: fix warning with AmigaOS.
- tool_operate: silence warning with AmigaOS
- amigaos: fix building libtests due to missing `RLIMIT_NOFILE`.
- curl_gethostname: silence warning for AmigaOS.
- ftp: silence `-Wtype-limits` for AmigaOS.
- libtest: fix timeval initialization for AmigaOS.
- examples: fix `timeval` initialization for AmigaOS.
- examples: silence warning for AmigaOS.
- configure: fix IPv6 detection for cross-builds.
- netrc: fix to build with AmigaOS cleanly.
- buildinfo: detect and add `DOS` tag for MS-DOS builds.
- buildinfo: add `AMIGA` to buildinfo.txt in auttools.
- build: move `USE_WATT32` macro definition to cmake/configure.
Non-MS-DOS/AmigeOS-specific tidy-ups:
- configure: sync `sa_family_t` detection with cmake.
- configure: sync `ADDRESS_FAMILY` detection signals with cmake.
- doh: use `CURL_SA_FAMILY_T`.
- lib: drop mingw-specific `CURL_SA_FAMILY_T` workaround.
- cmake: extend instead of override check-specific
configurations/requirements.
This allows to honor global requirements added earlier.
Necessary for AmigaOS for example.
- cmake: omit warning on disabled IPv6 for MS-DOS and AmigaOS.
No IPv6 support on these platforms. Also sync with autotools.
- lib1960: use libcurl `inet_pton()` wrapper.
- cmake: detect LibreSSL (to match autotools).
- cmake: say the specific OpenSSL flavour detected.
- hostip: add missing `HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID` guard.
- lib: simplify classic mac feature guards.
Follow-up to a8861b6ccd#9764Closes#15543
Enable `CURL_USE_PKGCONFIG` by default for MinGW cross-builds.
Note: This may cause fallouts in certain envs where `pkg-config` picks
up native packages.
Follow-up to e1ab01d1bd#14658
Follow-up to c555ab469d#14575Closes#15005
Prefix (or suffix) curl-defined macro and function names with `curl`.
To avoid collisions with non-curl CMake and to make them recognizable
as curl-specific calls.
Closes#15498
- drop `/clang:` prefix for `-W` options for clang-cl.
Except for `-Wall` which gets interpreted as MSVC `/Wall`
and translated to `-Weverything`, which is undesired.
Related: https://github.com/llvm/llvm-project/issues/102982
- include `MSVC_VERSION` in target flags.
Useful for clang-cl builds where this information doesn't appear
elsewhere in the cmake configure log.
- suppress `-Wlanguage-extension-token` more for clang-cl.
This fixes clang-cl builds with default `CURL_WERROR=OFF` and
`PICKY_COMPILER=ON`.
This warning is enabled by `-pedantic` as a warning and by
`-pedantic-errors` as an error. Verifiable using llvm's
`diagtool show-enabled -pedantic test.c`.
Follow-up to fb711b5098#15449Closes#15478
Move LDAP detection to its own Find module.
It supports `pkg-config` and the standard detection method used for
other dependencies, with version detection.
In curl CI it fixes LDAP detection in the OpenBSD job.
Closes#15273
- cmp-config.pl: add remaining exceptions. Sort list.
- drop unused `HAVE_SYS_WAIT_H`.
Follow-up to 50def7c881#13249
- drop unused `HAVE_FCHMOD`.
Follow-up to 03cb1ff4d6#12395
- autotools: stop promoting variables to macros:
`USE_NGTCP2_CRYPTO_*`, `USE_NGTCP2_H3`, `USE_OPENSSL_H3`,
`HAVE_LIBRESSL`.
They are not used in the source.
- cmake: drop unused `HAVE_O_NONBLOCK`,
`HAVE_DISABLED_NONBLOCKING`.
- lib: drop `NEED_MALLOC_H`.
It was used in manual-build cases for Amiga/MS-DOS/Windows/WinCE, but
never by autotools/cmake, thus apparently unnecessary.
- lib: drop unused `NEED_MEMORY_H`.
- lib: simplify classic mac feature guards,
drop `HAVE_EXTRA_STRICMP_H` and `HAVE_EXTRA_STRDUP_H`.
- autotools: drop unused `HAVE_GETHOSTBYNAME` detection.
- autotools: drop unused OpenSSL feature tests:
`HAVE_ERR_H`, `HAVE_PEM_H`, `HAVE_RSA_H`
- autotools: drop unused OpenSSL feature tests:
`HAVE_X509_H`, `HAVE_CRYPTO_H`, `HAVE_SSL_H`.
They performed a fallback check when the primary check missed
`openssl/x509.h`. Though if any other prefixed headers were found,
OpenSSL is already assumed detected.
The fallback check was looking for 3 unprefixed OpenSSL headers, and
if all found, marked OpenSSL found internally, but did not promote
it to `curl_config.h` via `USE_OPENSSL`. Meaning it either didn't do
anything or may have continued with an inconsistent state.
Added in d99c20f628 (2008)
At the time, there was an extra `AC_DEFINE(USE_SSLEAY, 1 ...` logic
after this code, which kicked in in the fallback case, but that code
was deleted in 709cf76f6b (2015)
Follow-up to 709cf76f6b
- autotools: drop `AC_SUBST()` where the value is explicitly set anyway
and the macro is unused.
- autotools: replace `AC_SUBST(VAR, 1)` with local variable assigments,
where the `@VAR@` macro is unused. Also dedupe the local variable if
there was a parallel one used for the same purpose.
- autotools: drop local feature variables that were never used.
- autotools: drop unused `CURL_CHECK_OPTION_NTLM_WB`,
`CURL_CHECK_NTLM_WB`.
Also stop setting unused `NTLM_WB_ENABLED` macro for VMS.
Follow-up to 50def7c881#13249
- autotools: drop unused `PKGADD_*`.
Follow-up to bae0d473f5#3331
- autotools: drop unused `CURL_NETWORK_LIBS`.
Follow-up to 3af75e18d6#14697Closes#15577
