Use lrand48 on Android

When building x86 assembly use lrand48 instead of the
undocumented inlined _rand function.

Android now supports rand()
https://android-review.googlesource.com/97731
but only for new versions. Original workaround:
https://gerrit.chromium.org/gerrit/15744

Change-Id: I130566837d5bfc9e54187ebe9807350d1a7dab2a