rebuild gcc rpm on x86_64

["Gene C." <czar czarc net>]

Can someone explain the logic to me why you need the i386 version of 
glibc-devel installed on a x86_64 system in order to rebuild gcc for the 
x86_64?  https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=113893

Besides the man and info files which are duplicates of the ones in the x86_64 
glibc-devel package, the i386 package only contains files in /usr/lib.

Yes, I am going to go and try to install it but I am sure bothered as to why.

An additional issue is that the i386 glibc-devel is not part of the FC1 x86_64 
test1 distribution (only glibc for the i686).  Shouldn't I be able to rebuild 
any package in a distribution given only the packages contained in the 
distribution?

Do I need the i386 version of glibc-devel to rebuild on the sparc?  How about 
the IA64 Itanium?
-- 
Gene