Fix error during cross-platform documentation.

Author: kennytm

src/libstd/sys/unix/ext/net.rs

@@ -12,8 +12,19 @@
 
 //! Unix-specific networking functionality
 
+#[cfg(unix)]
 use libc;
 
+// FIXME(#43348): Make libc adapt #[doc(cfg(...))] so we don't need these fake definitions here?
+#[cfg(not(unix))]
+mod libc {
+    pub use libc::c_int;
+    pub type socklen_t = u32;
+    pub struct sockaddr;
+    #[derive(Clone)]
+    pub struct sockaddr_un;
+}
+
 use ascii;
 use ffi::OsStr;
 use fmt;

src/libstd/sys/windows/c.rs

@@ -301,7 +301,7 @@ pub const PIPE_READMODE_BYTE: DWORD = 0x00000000;
 pub const FD_SETSIZE: usize = 64;
 
 #[repr(C)]
-#[cfg(target_arch = "x86")]
+#[cfg(not(target_pointer_width = "64"))]
 pub struct WSADATA {
     pub wVersion: WORD,
     pub wHighVersion: WORD,
@@ -312,7 +312,7 @@ pub struct WSADATA {
     pub lpVendorInfo: *mut u8,
 }
 #[repr(C)]
-#[cfg(target_arch = "x86_64")]
+#[cfg(target_pointer_width = "64")]
 pub struct WSADATA {
     pub wVersion: WORD,
     pub wHighVersion: WORD,
@@ -768,6 +768,14 @@ pub struct FLOATING_SAVE_AREA {
     _Dummy: [u8; 512] // FIXME: Fill this out
 }
 
+// FIXME(#43348): This structure is used for backtrace only, and a fake
+// definition is provided here only to allow rustdoc to pass type-check. This
+// will not appear in the final documentation. This should be also defined for
+// other architectures supported by Windows such as ARM, and for historical
+// interest, maybe MIPS and PowerPC as well.
+#[cfg(all(dox, not(any(target_arch = "x86_64", target_arch = "x86"))))]
+pub enum CONTEXT {}
+
 #[repr(C)]
 pub struct SOCKADDR_STORAGE_LH {
     pub ss_family: ADDRESS_FAMILY,