[Cleanup] fix builds to use pkgconfig --static

[heitbaum]

Libs.private which is declared in some of the .pc files needs to be used when linking with .a static libraries. Our build environment does not honor this presently.

try and build samba with libunwind and it fails with uncompress. This is because Libs.private is not picked up, a hack patch is currently in place to include the Libs.private in the Libs line.

This patch should be reverted once pkgconfig —static is used correctly.

some initial reading:

• https://fossies.org/linux/meson/mesonbuild/modules/pkgconfig.py
• https://linux.die.net/man/1/pkg-config
• https://stackoverflow.com/questions/27586503/how-to-use-pkg-config-to-link-a-library-statically
• libunwind.pc not including required -lz when statically compiled libunwind/libunwind#319

more info:

• vdr-plugin-xmltv2vdr with libzip does work correctly.

[heitbaum]

Issue with libopenmpt the same way.

• [le11] fix mpd build #6016

libunwind

• libunwind: build fix #5948