SwiftRemoteMirror: fix static library builds for Windows

We were previously treating all the builds as shared, which is not the
case for the host library build of SwiftRemoteMirror.  The warnings were
lost in the interminable spew from the build which is now fixed and this
stands out.

Author: compnerd

include/swift/SwiftRemoteMirror/Platform.h

@@ -23,15 +23,23 @@ extern "C" {
 # elif defined(__MACH__)
 #   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("default")))
 # else
-#   define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllexport)
+#   if defined(_WINDLL)
+#     define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllexport)
+#   else
+#     define SWIFT_REMOTE_MIRROR_LINKAGE
+#   endif
 # endif
 #else
 # if defined(__ELF__)
 #   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("default")))
 # elif defined(__MACH__)
 #   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("default")))
 # else
-#   define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllimport)
+#   if defined(_WINDLL)
+#     define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllimport)
+#   else
+#     define SWIFT_REMOTE_MIRROR_LINKAGE
+#   endif
 # endif
 #endif
 

stdlib/public/SwiftRemoteMirror/CMakeLists.txt

@@ -30,6 +30,7 @@ if(SWIFT_INCLUDE_TOOLS)
 
   add_swift_host_library(swiftRemoteMirror STATIC
     SwiftRemoteMirror.cpp)
+  target_compile_definitions(swiftRemoteMirror PRIVATE _LIB)
   target_compile_options(swiftRemoteMirror PRIVATE
     ${SWIFT_RUNTIME_CXX_FLAGS})
   set_property(TARGET swiftRemoteMirror APPEND_STRING PROPERTY LINK_FLAGS