[libpng15] Imported from libpng-1.5.15beta04.tar
[libpng15] Bump version to 1.5.15beta05
[libpng15] Use approved/supported Android method to check for NEON, use Linux/POSIX

1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
library calls.
[libpng15] Fix typo in previous arm patch
[libpng15] Use approved/supported Android method to check for NEON, use

Linux/POSIX 1003.1 API to check /proc/self/auxv avoiding buffer allocation
and other library calls.
[libpng15] Fixed typo in an #ifdef.
[libpng15] Use parentheses consistently in "#if defined()" tests.
[libpng15] Folded a long line, more consistent use of parentheses

in "#if defined()" tests.
[libpng15] Redo previous checkin; fold long lines and fix #ifdefs