alpha-dec-osf1 and alpha-dec-osf3 are now separate configurations.

AC_SUBST(exeext) added (only non-empty under cygwin32)

add note about 'make install-doc' to the message printed after
configuration.

Test for CC and GCC before finding CPP, since GNUCPP depends on
finding GCC to do the right thing.

fix dangling backquote in last commit.

Added feature tests for sed and cpp

IX/RS6000 patches

2.02 release update

Major update to more-or-less 2.02