In rpm-4.0-0.33, but also the current (2000-06-23) CVS, the optflags for
i486 have been set wrongly (and probably illegaly, i.e. nothing should
compile):

optflags: i486 -O2 -march=1486
                          ^

Furthermode, a deprecated form is used:

optflags: i386 -O2 -m486 -fno-strength-reduce
                   ^^^^^

info gcc (2.95.2) says:
--quote--
`-m386'
`-m486'
`-mpentium'
`-mpentiumpro'
     Synonyms for -mcpu=i386, -mcpu=i486, -mcpu=pentium, and
     -mcpu=pentiumpro respectively.  These synonyms are deprecated.
--endquote--

Perhaps you want to be using:

optflags: i386 -O2 -mcpu=i486 -fno-strength-reduce
(perhaps with -march=i386)