(This is more likely an autotools problem.)
GNU tar 1.22 still configured and built fine.
With 1.23 some shell-dependent code was introduced into makefile which
doesn't work with Unixware's /bin/sh (or make).
$ uname -a
UnixWare unixware 5 7.1.4 i386 x86at SCO UNIX_SVR5
$ sh configure --prefix=/usr/local
... seems to proceed without accidents ...
$ which make
/usr/bin/make
$ make
UX:make: WARNING: No suffix list.
make all-recursive
UX:make: WARNING: No suffix list.
Making all in doc
Making all in gnu
)rm -f alloca.h-t alloca.h && \
{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
cat ./alloca.in.h; \
} > alloca.h-t && \
mv -f alloca.h-t alloca.h
sh: syntax error at line 1: `)' unexpected
*** Error code 3 (bu21)
UX:make: ERROR: fatal error.
*** Error code 1 (bu21)
UX:make: ERROR: fatal error.
*** Error code 1 (bu21)
UX:make: ERROR: fatal error.
$
