In this commit enabled meson build infrastructure which is taking less
time than autotools to build.

Changes:
  - Same default value used for all build time configure option.
  - All external library checks are added into meson as well.
  - In meson, no need to mention list of files which are not required
    to install because, by default nothing will be installed.
  - Auto generated files are added into custom target and that will
    trigger when some target dependent with that.
  - In meson, enabled to treat warning as error so, modified few sources
    which are producing un-used variables.
        - Fixes made by removing those function parameters identifier alone.

By using meson, can able to see below built improvement time between meson
and autotools.

meson:
    - time sh -c 'meson builddir -Dhost-dump-offload-transport=pldm
       -Dubifs-workaround=enabled; ninja -C builddir/'
            real    0m12.244s
            user    0m57.575s
            sys     0m7.793s

autotools:
    - time sh -c 'autoreconf -i;
      ./configure ${CONFIGURE_FLAGS} --enable-ubifs-workaround
       --with-host-dump-offload-transport=pldm; make'
            real    1m16.539s
            user    1m2.738s
            sys     0m9.645s

TestedBy:
    - meson builddir
      ninja -C builddir

    - meson builddir -Dubifs-workaround=enabled
      ninja -C builddir

    - meson builddir -Dubifs-workaround=disabled
      ninja -C builddir

    - meson builddir -Dhost-dump-offload-transport=pldm
      ninja -C builddir

    - meson builddir -Dhost-dump-offload-transport=pldm \
                     -Dubifs-workaround=enabled
      ninja -C builddir

Note: Need to update openbmc phosphor-debug-collector recipe to use meson
      instead autotools, this will be updated once this patch got merged
      and also autotools build infrastructure will be removed as well.

Change-Id: Iadf2d3542dc2556377e7b2f91f01b04d5f8d7218
Signed-off-by: Ramesh Iyyar <rameshi1@in.ibm.com>