nassm.c: Use evaluate for section alignment
nassm.c: Use evaluate for section alignment

This allow us to write the whole expressions
on section alignments, such as

	align 0xa+6

or whatever math. Should be a way more convenient
than hardnumbers scheme we had.

Reported-by: Frank Kotler <576e266b023e5671b20b0df7a79abc544fa7199a@zytor.com>
Signed-off-by: Cyrill Gorcunov <7a1ea01eee6961eb1e372e3508c2670446d086f4@gmail.com>

letolabs/nasm,turingstudio/nasm,letolabs/nasm,techkey/nasm,Distrotech/nasm,techkey/nasm,letolabs/nasm,turingstudio/nasm,turingstudio/nasm,techkey/nasm,techkey/nasm,projedi/nasm,turingstudio/nasm,projedi/nasm,Distrotech/nasm,projedi/nasm,techkey/nasm,projedi/nasm,projedi/nasm,Distrotech/nasm,Distrotech/nasm