os: update unix and windows base.h

This adds additional macros from base.h to the windows and unix variants
to allow building dispatch on non-Apple targets.   This ensures that we
have:

- `SPI_AVAILABLE`
- `SPI_DEPRECATED`
- `OS_REFINED_FOR_SWIFT`
- `OS_SWIFT_NAME`

consistently across all the targets.

Author: compnerd

os/generic_unix_base.h

@@ -40,6 +40,14 @@
 #define API_DEPRECATED_WITH_REPLACEMENT(...)
 #endif
 
+#ifndef SPI_AVAILABLE
+#define SPI_AVAILABLE(...)
+#endif
+
+#ifndef SPI_DEPRECATED
+#define SPI_DEPRECATED(...)
+#endif
+
 #if __GNUC__
 #define OS_EXPECT(x, v) __builtin_expect((x), (v))
 #define OS_UNUSED __attribute__((__unused__))

os/generic_win_base.h

@@ -46,6 +46,14 @@ typedef void pthread_attr_t;
 #define API_DEPRECATED_WITH_REPLACEMENT(...)
 #endif
 
+#ifndef SPI_AVAILABLE
+#define SPI_AVAILABLE(...)
+#endif
+
+#ifndef SPI_DEPRECATED
+#define SPI_DEPRECATED(...)
+#endif
+
 #if !defined(__has_attribute)
 #define __has_attribute(attibute) 0
 #endif
@@ -99,6 +107,18 @@ typedef void pthread_attr_t;
 #define OS_SWIFT_UNAVAILABLE(msg)
 #endif
 
+#if __has_attribute(swift_private)
+# define OS_REFINED_FOR_SWIFT __attribute__((__swift_private__))
+#else
+# define OS_REFINED_FOR_SWIFT
+#endif
+
+#if __has_attribute(swift_name)
+# define OS_SWIFT_NAME(_name) __attribute__((__swift_name__(#_name)))
+#else
+# define OS_SWIFT_NAME(_name)
+#endif
+
 #define __OS_STRINGIFY(s) #s
 #define OS_STRINGIFY(s) __OS_STRINGIFY(s)