GC 4.6.0 introduced new warning: unused-but-set-variable, so with -Werror it's now impossible to build guile.
/bin/bash ../libtool --tag=CC --mode=compile powerpc-gnu-linux-uclibc-gcc -DHAVE_CONFIG_H -I.. -I.. -I.. -pthread -g -O2 -Wall -Wmissing-prototypes -Werror -MT libguile_la-async.lo -MD -MP -MF .deps/libguile_la-async.Tpo -c -o libguile_la-async.lo `test -f 'async.c' || echo './'`async.c libtool: compile: powerpc-gnu-linux-uclibc-gcc -DHAVE_CONFIG_H -I.. -I.. -I.. -pthread -g -O2 -Wall -Wmissing-prototypes -Werror -MT libguile_la-async.lo -MD -MP -MF .deps/libguile_la-async.Tpo -c async.c -fPIC -DPIC -o .libs/libguile_la-async.o async.c: In function 'scm_i_queue_async_cell': async.c:243:14: error: variable 'count' set but not used [-Werror=unused-but-set-variable] cc1: all warnings being treated as errors make[3]: *** [libguile_la-async.lo] Error 1
