-fandroid-pad-segment is an Android-specific opt-in option that
links in crt_pad_segment.o (beside other crt*.o relocatable files).
crt_pad_segment.o contains a note section, which will be included in the
linker-created PT_NOTE segment. This PT_NOTE tell Bionic that: when
create a map for a PT_LOAD segment, extend the end to cover the gap so
that we will have fewer kernel 'struct vm_area_struct' objects when
page_size < MAXPAGESIZE.
See also https://sourceware.org/bugzilla/show_bug.cgi?id=31076
Link: https://r.android.com/2902180
5133a8f559