On Windows POSIX layers, two files are produced for a shared library,
there's {shlibname}.dll and there's the import library {libname}.dll.a

On some/most Unix platforms, a {shlibname}.{sover}.so and a symlink
{shlibname}.so are produced.

For each of them, unix-Makefile.tmpl was entirely consistent on which
to have as a target when building a shared library or which to use as
dependency.

This change clears this up and makes it consistent, we use the
simplest form possible, {lib}.dll.a on Windows POSIX layers and
{shlibname}.so on Unix platforms.  No exception.
Reviewed-by: NRich Salz <rsalz@openssl.org>

Because the command line definitions of OPENSSLDIR and ENGINESDIR
contain quotes, we need a variant of CFLAG where backslashes and
quotes are escaped when we produce buildinf.h
Reviewed-by: NRich Salz <rsalz@openssl.org>

Cygwin and Mingw name their libraries a bit differently from the rest
of the POSIXly universe, we need to adapt to that.

In Makefile.tmpl, it means that some hunks will only be output
conditionally.

This also means that shared_extension for the Cygwin and Mingw
configurations in Configurations/10-main.conf are changing from .dll.a
to .dll.  Makefile.shared does a fine job without having them
specified, and it's much easier to work with tucking an extra .a at
the end of files in the installation recipes than any amount of name
rewrites, especially with the support of the SHARED_NAME in the top
build.info.
Reviewed-by: NRich Salz <rsalz@openssl.org>

This also adds all the raw sections needed for some files.
Reviewed-by: NRich Salz <rsalz@openssl.org>