> Simplify the iconv-emits-BOM check that we have in Meson a bit by:
> 
>   - Dropping useless variables.
> 
>   - Casting the `inpos` pointer to `void *` instead of using a typedef
>     that depends on whether or not we use an old iconv library.
> 
> This overall condenses the code signficantly and makes it easier to
> follow.
> 
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  meson.build | 56 ++++++++++++++++++++------------------------------------
>  1 file changed, 20 insertions(+), 36 deletions(-)
> 
> diff --git a/meson.build b/meson.build
> index 4b536e0124..ee3d9ced92 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -1040,42 +1040,26 @@ if iconv.found()
>      have_old_iconv = true
>    endif
>  
> -  iconv_omits_bom_source = '''#
> -    #include <iconv.h>
> -
> -    int main(int argc, const char **argv)
> -    {
> -  '''
> -  if have_old_iconv
> -    iconv_omits_bom_source += '''
> -      typedef const char *iconv_ibp;
> -    '''
> -  else
> -    iconv_omits_bom_source += '''
> -      typedef char *iconv_ibp;
> -    '''
> -  endif
> -  iconv_omits_bom_source += '''
> -      int v;
> -      iconv_t conv;
> -      char in[] = "a"; iconv_ibp pin = in;
> -      char out[20] = ""; char *pout = out;
> -      size_t isz = sizeof in;
> -      size_t osz = sizeof out;
> -
> -      conv = iconv_open("UTF-16", "UTF-8");
> -      iconv(conv, &pin, &isz, &pout, &osz);
> -      iconv_close(conv);
> -      v = (unsigned char)(out[0]) + (unsigned char)(out[1]);
> -      return v != 0xfe + 0xff;
> -    }
> -  '''
> -
> -  if meson.can_run_host_binaries() and compiler.run(iconv_omits_bom_source,
> -    dependencies: iconv,
> -    name: 'iconv omits BOM',
> -  ).returncode() != 0
> -    libgit_c_args += '-DICONV_OMITS_BOM'
> +  if meson.can_run_host_binaries()
> +    if compiler.run('''
> +      #include <iconv.h>
> +
> +      int main(int argc, const char **argv)
> +      {
> +        char in[] = "a", *inpos = in;
> +        char out[20] = "", *outpos = out;
> +        size_t insz = sizeof(in), outsz = sizeof(out);
> +        iconv_t conv = iconv_open("UTF-16", "UTF-8");
> +        iconv(conv, (void *) &inpos, &insz, &outpos, &outsz);

> In d0cec08d70 (utf8.c: prepare workaround for iconv under macOS 14/15,
> 2026-01-12) we have introduced a new workaround for a broken version of
> libiconv on macOS. This workaround has for now only been wired up for
> our Makefile, so using Meson with such a broken version will fail.
> 
> We can rather easily detect the broken behaviour. Some encodings have
> different modes that can be switched to via an escape sequence. In the
> case of ISO-2022-JP this can be done via "<Esc>$B" and "<Esc>(J" to
> switch between ASCII and JIS modes. The bug now triggers when one does
> multiple calls to iconv(3p) to convert a string piece by piece, where
> the first call enters JIS mode. The second call forgets about the fact
> that it is still in JIS mode, and consequently it will incorrectly treat
> the input as ASCII, and thus the produced output is of course garbage.
> 
> Wire up a test that exercises this in Meson and, if it fails, set the
> `ICONV_RESTART_RESET` define.

> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  meson.build | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/meson.build b/meson.build
> index ee3d9ced92..1b9be3d36c 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -1060,6 +1060,32 @@ if iconv.found()
>      ).returncode() != 0
>        libgit_c_args += '-DICONV_OMITS_BOM'
>      endif
> +
> +    if compiler.run('''
> +      #include <iconv.h>
> +      #include <string.h>
> +
> +      int main(int argc, const char *argv[])
> +      {
> +          char in[] = "\x1b\x24\x42\x24\x22\x24\x22\x1b\x28\x42", *inpos = in;

> +          char out[7] = { 0 }, *outpos = out;
> +          size_t insz = sizeof(in) - 1, outsz = 4;
> +          iconv_t conv = iconv_open("UTF-8", "ISO-2022-JP");
> +          if (!conv)
> +              return 1;
> +          if (iconv(conv, (void *) &inpos, &insz, &outpos, &outsz) != (size_t) -1)
> +              return 2;
> +          outsz = sizeof(out) - (outpos - out);
> +          if (iconv(conv, (void *) &inpos, &insz, &outpos, &outsz) == (size_t) -1)
> +              return 3;

> +      }
> +    ''',
> +      dependencies: iconv,
> +      name: 'iconv handles restarts properly',
> +    ).returncode() != 0

> +      libgit_c_args += '-DICONV_RESTART_RESET'
> +    endif
>    endif
>  else
>    libgit_c_args += '-DNO_ICONV'

> The macos-14-xcode-15 images for GitLab's macOS runners have been
> deprecated. Update to macOS 15, which is our current stable version.
> 
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  .gitlab-ci.yml | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
> index 71b8a6e642..83ec786c5a 100644
> --- a/.gitlab-ci.yml
> +++ b/.gitlab-ci.yml
> @@ -101,13 +101,13 @@ test:osx:
>    parallel:
>      matrix:
>        - jobname: osx-clang
> -        image: macos-14-xcode-15
> +        image: macos-15-xcode-16
>          CC: clang
>        - jobname: osx-reftable
> -        image: macos-14-xcode-15
> +        image: macos-15-xcode-16
>          CC: clang
>        - jobname: osx-meson
> -        image: macos-14-xcode-15
> +        image: macos-15-xcode-16
>          CC: clang
>    artifacts:
>      paths: