caches: add a cache for a i686 build of the runtime on Windows

This adds a cache for a configuration of the standard library for
Windows x86 configurations.  This should help restore the x86 builds of
the SDK for Windows.

Author: compnerd

cmake/caches/Runtime-Windows-i686.cmake

@@ -0,0 +1,21 @@
+
+set(SWIFT_HOST_VARIANT_SDK WINDOWS CACHE STRING "")
+set(SWIFT_HOST_VARIANT_ARCH i686 CACHE STRING "")
+
+# NOTE(compnerd) disable the tools, we are trying to build just the standard
+# library.
+set(SWIFT_INCLUDE_TOOLS NO CACHE BOOL "")
+
+# NOTE(compnerd) cannot build tests since the tests require the toolchain
+set(SWIFT_INCLUDE_TESTS NO CACHE BOOL "")
+
+# NOTE(compnerd) cannot build docs since that requires perl
+set(SWIFT_INCLUDE_DOCS NO CACHE BOOL "")
+
+# NOTE(compnerd) these are part of the toolchain, not the runtime.
+set(SWIFT_BUILD_SYNTAXPARSERLIB NO CACHE BOOL "")
+set(SWIFT_BUILD_SOURCEKIT NO CACHE BOOL "")
+
+# NOTE(compnerd) build with the compiler specified, not a just built compiler.
+set(SWIFT_BUILD_RUNTIME_WITH_HOST_COMPILER YES CACHE BOOL "")
+