[openssl] Fix build with "C:\Program Files\<...>\cl.exe"

[dg0yt]

This fixes the long-standing annoyance that port openssl fails to build with (some) installations of Visual Studio to paths including the space character, also affecting the default location C:\Program Files\Visual Studio\....

The port passes the absolute path of CC and the CFLAGS as detected from the CMake toolchain.
This works for all normal build rules, but not for the invocation of a perl scripts which is meant to write that information into crypto/buildinf.h which is created via this rule:

$(PERL) <SRCDIR>/util/mkbuildinf.pl "$(CC) $(LIB_CFLAGS) $(CPPFLAGS_Q)" "$(PLATFORM)" > $@

• The rule doesn't properly handle quotes in CC or flags (at least for Windows host), so perl may see multiple arguments when it expects to see exactly two arguments.
• mkbuildinf.pl doesn't consider the backslash in filepaths like CC when constructing a C string.

The new patch

• handles multiple arguments, assuming only that the last one is the platform.
• quotes all backslashes for C string construction.

NB the full path of the compiler is written as build information into binary aritfacts. If this isn't desired, a different approach must be taken.

Resolves #42740.
Resolves #41751.
Resolves #39912.
Resolves #38723.
Resolves #36175.
Related:

• [windows] crypto/buildinf.h is generated incorrectly if path to compiler has spaces openssl/openssl#26253
• Previous analysis: [openssl] Build error on x64-windows #37134 (comment)
• Previous attempt: [openssl] Enforce cmd for nmake #37716
• Previous issues: https://github.com/microsoft/vcpkg/issues?q=is%3Aissue%20state%3Aclosed%20openssl%20cversion.c

[dg0yt]

Upstream: openssl/openssl#26315.

[jimwang118]

Compile test pass with following triplets:

x86-windows
x64-windows
x86-windows-static