The Emacs 28.1 distribution tarball does not unpack correctly on Solaris 
10 when using the system-supplied 'tar' program. This is a regression 
from Emacs 27.2. I didn't pick this up when testing earlier, since I 
have GNU 'tar' in my PATH (perhaps I shouldn't; oh well). The symptoms are:

   $ gzip -d <emacs-28.1.tar.gz | tar xf -
   tar: ././@LongLink: typeflag 'L' not recognized, converting to 
regular file
   tar: ././@LongLink: typeflag 'L' not recognized, converting to 
regular file
   ...

The problem is that the Emacs 28.1 tarball (unlike 27.2) has file names 
longer than 100 bytes. These file names do not fit within traditional 
'tar' format. By default, for these files GNU Tar uses a GNU-specific 
@LongLink extension, designed long ago but not picked up by POSIX, that 
Solaris 10 tar does not understand.

A simple workaround is to tell GNU Tar to generate POSIX-standard 
tarballs instead. I installed the attached patch to Emacs master to fix 
this, and suggest that it be backported to the Emacs 28 branch if we're 
planning to generate another Emacs 28 version.