building gnucash with guile-1.8

[Stuart McGraw]

I was able to build gnucash-2.6.1 on my ancient Fedora-15
system with guile-1.8.8 using the standard "./configure && 
make install" dance with no problems.

But when I try with gnucash-2.6.4. ./configure complains:

 [...]
 checking for guile-1.8 >= 1.8.5... yes
 checking GUILE_CFLAGS... -pthread  
 checking GUILE_LIBS... -lguile  
 checking for guile... /usr/bin/guile
 checking for Guile version >= 2.0... configure: error: Guile 2.0 required, but 1.8.8 found

README.dependencies says guile >= 1.8.5 is ok. I did not see anything
in the NEWS file about dropped support for guile-1.8.  

Can/How do I get gnucash to build with guile-1.8?