-no-undefined vs gcc 4.6.0

[LRN]

Since gcc 4.6.0 it is no longer possible to use LDFLAGS=-no-undefined
gcc now says something like this:
gcc.exe: error: unrecognized option '-no-undefined'
Before 4.6.0 it was possible to do that, and gcc said only this:
gcc.exe: unrecognized option '-no-undefined'
That is, unrecognized option was not considered a show-stopper, and 
everything worked just fine - the option, being part of LDFLAGS, 
eventually reached libtool, and libtool were taking the clue to disallow 
undefined symbols. Not anymore. Now i have to pass 
LDFLAGS=-Wl,-no-undefined. Which is ok from gcc' point of view, but 
libtool is unable to recognize this argument in such form and simply 
refuses to build shared libraries outright.
Not sure if it's a bug or a feature, and how to work through that 
without making groundbreaking changes in software packages that use libtool.