Wasm module is now not built for Amazon Linux 2, Debian 11 and Ubuntu
2.0.04, since it requires cmake version newer than what's available on
those OSes.  wasm-wasi-component is not affected.

Closes: https://github.com/nginx/unit/issues/915
Closes: https://github.com/nginx/unit/issues/1178

The 'Group' and 'BuildRoot' tags have been declared as deprecated by the
Fedora project.

Also, to quote the Fedora Packaging Guidelines

  The contents of the buildroot SHOULD NOT be removed in the first line
  of %install.

  The %defattr directive in the %files list SHOULD ONLY be used when
  setting a non-default value, or to reset to the default value after
  having set a non-default value.

Link: <https://fedoraproject.org/wiki/RPMGroups>
Link: <https://fedoraproject.org/wiki/Phase_out_buildroot_tag_(draft)>
Link: <https://fedoraproject.org/wiki/Archive:PackagingDrafts/BuildRoot>
Link: <https://docs.fedoraproject.org/en-US/packaging-guidelines/#_tags_and_sections>
[ Tweaked subject & added commit message - Andrew ]
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

Forgotten in bf3d5759e and 260494626.

This extends the approach used for debian-based packages in 3f805bc64e28
to rpm as well.  Notable change for both deb and rpm packaging is to use
CFLAGS as defined in the build/Makefile, and not pass them from the
environment which might not be there (as is the case for rpm).

While at it, stop passing CFLAGS in the install phase, as it should no
longer invoke builds (see d54af163c46b).

The rpm part was overlooked in 7a6405566c0, since testing was not done
on the platforms where problem manifested itself, notably Amazon Linux
2023 and Fedora 38+.