computation of arch and machine type so it's worked out before
some_aout_object_p is called.
* aoutx.h: (some_aout_object_p): don't set arch and mach to
unknown.
* archures.c: add extra field 'section_align_power' to hold
default section alignment in object files.
* cpu-a29k.c, cpu-h8300.c, cpu-i386.c, cpu-i960.c, cpu-m68k.c,
cpu-m88k.c, cpu-mips.c, cpu-rs6000.c, cpu-sparc.c, cpu-vax.c:
initialize the new field.
* bout.c (b_out_callback): replace the text size, since aout
fries them.
* aoutx.h: Documentation in the new style
