Merge branch 'PR/autotools-pkg-config-libs' of https://github.com/karelzak/util-linux...

* 'PR/autotools-pkg-config-libs' of https://github.com/karelzak/util-linux-work:
  autotools: fix AM_CONDITIONAL for HAVE_UDEV and HAVE_AUDIT
  autotools,meson: drop unnecessary libm from test_pty
  autotools: split MATH_LIBS and ISNAN_LIBS
  autotools: use PKG_CHECK_MODULES for zlib
  autotools: use PKG_CHECK_MODULES for libcap-ng
  autotools: use PKG_CHECK_MODULES for libaudit
  autotools: use PKG_CHECK_MODULES for libudev
  autotools: use $(MATH_LIBS) instead of -lm for hwclock
  autotools: use $(SQLITE3_LIBS) instead of -lsqlite3
  autotools: use $(SELINUX_LIBS) instead of -lselinux
  autotools: use $(ECONF_LIBS) instead of -leconf