Re: time_rz.c and Android NDK r27

[Bruno Haible]

Hi Po Lu,

> This new release of the Android NDK defines timezone_t in time.h whether
> or not it defines the related tzalloc and localtime_rz extensions, which
> being new APIs are controlled by __ANDROID_API__ as expected.
> Consequently, when building for earlier Android releases with this NDK,
> Emacs compilation reports:
> 
>   CC       nproc.o
>   CC       nstrftime.o
> In file included from nstrftime.c:19:
> ./strftime.c:1900:17: error: call to undeclared function 'mktime_z'; ISO C99 
> and later do not support implicit function declarations 
> [-Wimplicit-function-declaration]
>  1900 |             t = mktime_z (tz, &ltm);
>       |                 ^
> ./strftime.c:1900:17: note: did you mean 'mktime'?
> /opt/android/android-ndk-r27/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/time.h:159:8:
>  note: 'mktime' declared here
>   159 | time_t mktime(struct tm* _Nonnull __tm);
>       |        ^
> 1 error generated.

Thanks for the report. The major mistake we've been doing here is to
assume that the presence of timezone_t is equivalent to the presence of the
functions tzalloc, tzfree, localtime_rz, mktime_z.

The following patches should fix it. Tested only on glibc systems and NetBSD.
If you could test it on Android, with
  CC="clang -target armv7a-unknown-linux-android34"
and
  CC="clang -target armv7a-unknown-linux-android35"
that would be welcome!

Bruno


2024-09-04  Bruno Haible  <bruno@clisp.org>

        Resolve conflicts for functions introduced in Android API level 35.

        Reported by Po Lu <luangruo@yahoo.com> in
        <https://lists.gnu.org/archive/html/bug-gnulib/2024-09/msg00024.html>.
        * lib/time.in.h (timezone_t, tzalloc, tzfree): Don't require _GNU_SOURCE
        to be defined. Define depending on HAVE_TZALLOC, not HAVE_TIMEZONE_T.
        (localtime_rz, mktime_z): Likewise. Override if REPLACE_LOCALTIME_RZ or
        REPLACE_MKTIME_Z is 1, respectively.
        * lib/time_rz.c: If NEED_TIMEZONE_NULL_SUPPORT, define only localtime_rz
        and mktime_z and only as wrappers around the system function.
        * m4/time_h.m4 (gl_TIME_H_DEFAULTS): Initialize HAVE_TZALLOC,
        REPLACE_LOCALTIME_RZ, REPLACE_MKTIME_Z.
        * m4/time_rz.m4 (gl_TIME_RZ): Conditionally set HAVE_TZALLOC,
        REPLACE_LOCALTIME_RZ, REPLACE_MKTIME_Z. Conditionally define
        NEED_TIMEZONE_NULL_SUPPORT.
        * modules/time-h (Makefile.am): Substitute HAVE_TZALLOC,
        REPLACE_LOCALTIME_RZ, REPLACE_MKTIME_Z.
        * modules/time_rz (Depends-on, configure.ac): Consider HAVE_TZALLOC,
        REPLACE_LOCALTIME_RZ, REPLACE_MKTIME_Z. Ignore HAVE_TIMEZONE_T.

        * m4/strerrorname_np.m4 (gl_FUNC_COPY_FILE_RANGE): Conditionally set
        REPLACE_STRERRORNAME_NP.
        (gl_CHECK_STRERRORNAME_NP): Test for strerrorname_np using
        gl_CHECK_FUNCS_ANDROID instead of AC_CHECK_FUNCS.

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