POSIX standard specifies that wait.h should be in sys/wait.h and
fcntl.h at top-level, not under sys. This is true for all unix systems,
even glibc. glibc provides wait.h and sys/fcntl.h, but these just
includes the same-named headers from the correct locations.

The current makefiles generate invalid LD_LIBRARY_PATHs like:

    LD_LIBRARY_PATH="../alib2std/lib-release;../alib2common/lib-release;lib-release" test-bin-release/alib2test

Standard directory separator on Unix/Linux systems is a colon. I found
that semicolon may be used to separate two lists of directories - the
first one is searched before the list(s) supplied on the command line,
the second one is searched after. But that's apparently not the case
here.

It seems that glibc doesn't care about it, because it somehow works on
Jenkins that runs on Gentoo. However, more correct libc libraries, like
musl libc, do care about it and don't accept such LD_LIBRARY_PATH.

This reverts commit 8e70f865.