This has been reported on the samba mailing list by Oliver Weinmann and William Edward Wilson.
Linking shared library in/libtalloc.so
ln: cannot create bin/libtalloc.so.1: File exists
*** Error code 2
make: Fatal error: Command failed for target `bin/libtalloc.so'
The problem is that ln -s -f fails on Solaris when the link already exists.
The issue is (should be) fixed in v3-3-test. But since this is part of a bigger rewrite of the library build system, I am filing a separate bug for 3.2.0.
Will be in 3.2.2.
Closing out bug report.