[breaking change] PTRACE_GETFPXREGS and PTRACE_SETFPXREGS were incorrectly re-exported on arm but they are x86 specific

defined for 32-bit Solarish targets.  Since rust doesn't currently
support 32-bit Solarish targets, the line is both unnecessary and wrong.

-   fix syntax error in expand_align macro
-   fix errors due to doubly defined symbols / functions for
    x86_64-uclibc

while here, generate the right file in test_openbsd()