Update buildenv

[DNikolaevAtRocket]

• Build the in-tree extensions that don't have big-endian related issues.
• Use -fvisibility=default to make DuckDB DLL work.

[DNikolaevAtRocket]

Hi @IgorTodorovskiIBM and @v1gnesh,

After patching upstream, It's buildable for our project, but there are a couple of issues when building this with zopen:

• It appears that ZOPEN_MAKE_OPTS are not applied (neither GEN=ninja nor newly added ones), and I don't see the top-level make even being called.

• The latest DuckDB uses anonymous mmap for block allocator which is available only on v3.1+
  It's fine for us, but not sure how to handle it here.

Any thoughts?