build: Fix build script output option

[johannes-wolf]

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Description

Using the build.sh scripts -o flag did not set the zserio_extensions.{build_dir,install_dir}, which resulted in a zserio build with the extensions missing.

We switched to using the build.sh with the -o flag in zserio-cmake-helper with commit Klebert-Engineering/zserio-cmake-helper@9a446ab in favour of calling ant directly.

Type of Change

• Bug fix
• New feature
• Documentation enhancement

[mikir]

Thanks a lot for that! These variables was completelly missing.

Actually, this ANT_PROPS could be improved and split them up for zserio core and extension. We will do it afterwards.