configure.ac: Simplify version comparisons
configure.ac: Simplify version comparisons

Use AS_VERSION_COMPARE to properly compare gcc and libtool versions
in configure.ac.

pcqpcq/sox,uklauer/sox,CaptainHayashi/sox,uklauer/sox,cbagwell/sox,uklauer/sox,pcqpcq/sox,pcqpcq/sox,cbagwell/sox,CaptainHayashi/sox,CaptainHayashi/sox,CaptainHayashi/sox,cbagwell/sox,cbagwell/sox,pcqpcq/sox,uklauer/sox