$ rpm --target i586-pc-linux --showrc | head -n 10
ARCHITECTURE AND OS:
build arch            : i586
compatible build archs: i586
build os              : Linux
compatible build os's : linux
install arch          : i586
install os            : Linux
compatible archs      : i586
compatible os's       : linux
optflags              : -O2 -g -m32 -march=i586 -fasynchronous-unwind-tables