Build problem: error: ‘size_t’ does not name a type

We started getting this error in the CI building Mir for landing-016, and can repro locally using cross-compile, also.

"...
In file included from /home/camako/work/partial-armhf-chroot/usr/include/android/hardware/hardware.h:24:0,
                 from /home/camako/workspace/03-land/src/platform/graphics/android/android_graphic_buffer_allocator.h:23,
                 from /home/camako/workspace/03-land/tests/unit-tests/graphics/android/test_android_buffer_allocator.cpp:19:
/home/camako/work/partial-armhf-chroot/usr/include/android/system/graphics.h:269:5: error: ‘size_t’ does not name a type
     size_t ystride;
     ^
/home/camako/work/partial-armhf-chroot/usr/include/android/system/graphics.h:270:5: error: ‘size_t’ does not name a type
     size_t cstride;
     ^
/home/camako/work/partial-armhf-chroot/usr/include/android/system/graphics.h:271:5: error: ‘size_t’ does not name a type
     size_t chroma_step;
..."