Fingers crossed...
Nope! Same error:
checking for fabsl declaration...
/home/mz/gcc-test/build/src/gcc-4.5.2/libiberty/strsignal.c:554:1:
error: conflicting types for 'psignal'
/home/mz/gcc-test/install/powerpc-unknown-linux-gnu/powerpc-unknown-linux-gnu/sysroot/usr/include/signal.h:150:13:
note: previous declaration of 'psignal' was here
make[3]: *** [strsignal.o] Error 1
make[3]: *** Waiting for unfinished jobs....
yes
checking for fabsl... make[3]: Leaving directory
`/home/mz/gcc-test/build/powerpc-unknown-linux-gnu/build/build-cc/powerpc-unknown-linux-gnu/libiberty'
make[2]: *** [all-target-libiberty] Error 2
make[2]: *** Waiting for unfinished jobs....
no
I am backtracking now and using 2.20.1 and see if this cures it...