Hi Christophe,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on next-20200130]
[cannot apply to powerpc/next tip/timers/vdso mpe/next v5.5 v5.5-rc7 v5.5-rc6 v5.5]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/powerpc-switch-VDSO-to-C-implementation/20200202-175410
base:    c32e1d01a152aee976763ccf7c7ced53ca45b78f
config: powerpc-defconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 7.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.5.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> arch/powerpc/kernel/vdso32/vgettimeofday.c:26:1: error: unknown type name 'time_t'; did you mean 'ktime_t'?
    time_t __c_kernel_time(time_t *time, const struct vdso_data *vd)
    ^~~~~~
    ktime_t
   arch/powerpc/kernel/vdso32/vgettimeofday.c:26:24: error: unknown type name 'time_t'; did you mean 'ktime_t'?
    time_t __c_kernel_time(time_t *time, const struct vdso_data *vd)
                           ^~~~~~
                           ktime_t
--
>> arch/powerpc/kernel/vdso64/vgettimeofday.c:26:1: error: unknown type name 'time_t'; did you mean 'ktime_t'?
    time_t __c_kernel_time(time_t *time, const struct vdso_data *vd)
    ^~~~~~
    ktime_t
   arch/powerpc/kernel/vdso64/vgettimeofday.c:26:24: error: unknown type name 'time_t'; did you mean 'ktime_t'?
    time_t __c_kernel_time(time_t *time, const struct vdso_data *vd)
                           ^~~~~~
                           ktime_t

vim +26 arch/powerpc/kernel/vdso32/vgettimeofday.c

    25	
  > 26	time_t __c_kernel_time(time_t *time, const struct vdso_data *vd)

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0-DAY kernel test infrastructure                 Open Source Technology Center
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