Make libcore compile with BoringSSL.

NativeBN_putULongInt was cleaned up because of a slightly worrying mix
of signed and unsigned ints, and because of an unneeded preprocessor
test. However, as I look down the rest of the file, there's a lot of it
but I didn't get to fixing it all up.

Bug: 17409664
Change-Id: If0adde83bebf04e7e3be163c1b30ebef75a67d05
Signed-off-by: Adam Langley <agl@google.com>
2 files changed