reintroduce install -C option if available use predefined autoconf macro to check for obstacks
reintroduce install -C option if available
use predefined autoconf macro to check for obstacks

[r631]

davidgiven/libfirm,8l/libfirm,killbug2004/libfirm,libfirm/libfirm,MatzeB/libfirm,8l/libfirm,MatzeB/libfirm,killbug2004/libfirm,jonashaag/libfirm,jonashaag/libfirm,jonashaag/libfirm,MatzeB/libfirm,davidgiven/libfirm,killbug2004/libfirm,killbug2004/libfirm,davidgiven/libfirm,killbug2004/libfirm,jonashaag/libfirm,libfirm/libfirm,killbug2004/libfirm,jonashaag/libfirm,MatzeB/libfirm,jonashaag/libfirm,libfirm/libfirm,8l/libfirm,MatzeB/libfirm,8l/libfirm,libfirm/libfirm,davidgiven/libfirm,MatzeB/libfirm,libfirm/libfirm,davidgiven/libfirm,killbug2004/libfirm,davidgiven/libfirm,MatzeB/libfirm,8l/libfirm,8l/libfirm,jonashaag/libfirm,8l/libfirm,davidgiven/libfirm