tcl can use its internal zlib. If it detects zlib during configure, then it
gets removed from the sysroot during the build (since its no in DEPENDS),
it causes build failures.
Worse, if the configure test fails to find zlib, it still appents -lz to
the other autoconf tests meaning several fail when they shouldn't. This results
in conflicts with system macros and other bizarre issues.
The easiest fix is to depend on zlib-native and make things determinstic.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
