Libogg and libtheora: build on windows (#35099)

Adds builders appropriate for building these packages on Windows.
It is intended that builds on other platforms are unaffected (e.g.
they build with Autotools as before on Linux).

lib/spack/spack/compilers/msvc.py

@@ -122,7 +122,19 @@ def platform_toolset_ver(self):
     @property
     def cl_version(self):
         """Cl toolset version"""
-        return spack.compiler.get_compiler_version_output(self.cc)
+        return Version(
+            re.search(
+                Msvc.version_regex,
+                spack.compiler.get_compiler_version_output(self.cc, version_arg=None),
+            ).group(1)
+        )
+
+    @property
+    def vs_root(self):
+        # The MSVC install root is located at a fix level above the compiler
+        # and is referenceable idiomatically via the pattern below
+        # this should be consistent accross versions
+        return os.path.abspath(os.path.join(self.cc, "../../../../../../../.."))
 
     def setup_custom_environment(self, pkg, env):
         """Set environment variables for MSVC using the