For whatever reason OpenSSL wants to use "masm" (ml.exe) on 32-bit
builds but "nasm" on 64-bit builds - this despite INSTALL.W32 claiming
that only nasm is "supported".

But /safeseh doesn't make sense on 64-bit anyway because there
is no "unsafe" SEH there, so just apply the patch only for 32-bit.

Change-Id: Ie32b17dfeeaf11c49ee29c3181021ffa5bd99091