This is particularly useful in cross-compile situations, where a wrapper
around pkg-config is sometimes needed.

This is done in a cross-compile-friendly manner with cpp rather than
uname. printf is used rather than echo due to inconsistent handling of
the -e option across different shells.

It has provided one since version 1.5. It erroneously hardcodes the
libdir as "lib" (it may be lib64), but OwnTracks defaulted to "lib"
anyway. I will fix Mosquitto shortly.

ot-record creates it automatically. Other directories are also created
automatically, so we should be consistent here. Note that some package
managers need special handling for empty directories at build time, but
they don't care about directories created at runtime.

As the Linux kernel experiment with this flag has shown, it's just a bad
idea unless you regularly do development work on the project. Different
compilers and compiler versions will emit different warnings, which will
cause headaches for users.