Impossible to compile Celestia 1.6.4 on Debian 11

[TCH68k]

I've downloaded Celestia 1.6.4's sources from here, extracted it, then i did:

libtoolize
autoreconf -f
./configure --with-gtk

libtoolize (v2.4.6) finishes silently.
autoreconf (v2.72) throws a bunch of warnings, but finishes.
configure dies with an error:

./configure: line 30782: syntax error near unexpected token `fi'
./configure: line 30782: `fi'

Complete logs:
http://oscomp.hu/depot/celestia_1.6.4_autoreconf.log
http://oscomp.hu/depot/celestia_1.6.4_configure.log

[375gnu]

Could you provide configure script?

[TCH68k]

Yes, i have uploaded it to here: configure.txt