Description of problem:
Use of "Prefix: /foo" will silently redefine macro %{prefix} 
to "/foo". This seems like either a bug or a bad idea because the 
macro is not "_prefix" or "__prefix", just a plain "prefix", hence it 
is not expected that it gets manipulated behind the scenes. (See Red 
Hat RPM Guide, p.305)

Also, this feature is not documented in Red Hat RPM Guide, p.222)


Version-Release number of selected component (if applicable):
rpm-4.2.1-4.2

How reproducible:
always

Steps to Reproduce:
1.  %define prefix /foo
2.  Prefix: %{prefix}
3.  Prefix: /anotherprefix
4.  %{error: value is %{prefix}}

Actual results:
error:  value is /anotherprefix

Expected results:
error:  value is /foo

Additional info: