Conditional-compile against minimal tcmalloc.

Conditional-compile against minimal tcmalloc.

Certain older systems (SLE11 in this case) do not provide the full
tcmalloc functionality, due to e.g. incomplete libunwind
pieces. Use --with-tcmalloc-minimal to enable the cut-down
version.

Here's how the various mem allocator switches interact now:

--with-jemalloc: overrides --with-tcmalloc & --with-tcmalloc-minimal
--with-tcmalloc-minimal: overrides --with-tcmalloc
--with-tcmalloc: the default. use --without-tcmalloc to disable

Signed-off-by: Thorsten Behrens <tbehrens@suse.com>