Rollup merge of rust-lang#30925 - semarie:blksize_t, r=alexcrichton

make `os::raw::tests::unix` test to pass again

r? @alexcrichton

Author: Manishearth

src/libstd/os/openbsd/raw.rs

@@ -16,7 +16,7 @@ use os::raw::c_long;
 use os::unix::raw::{uid_t, gid_t};
 
 #[stable(feature = "raw_ext", since = "1.1.0")] pub type blkcnt_t = i64;
-#[stable(feature = "raw_ext", since = "1.1.0")] pub type blksize_t = u32;
+#[stable(feature = "raw_ext", since = "1.1.0")] pub type blksize_t = i32;
 #[stable(feature = "raw_ext", since = "1.1.0")] pub type dev_t = i32;
 #[stable(feature = "raw_ext", since = "1.1.0")] pub type fflags_t = u32;
 #[stable(feature = "raw_ext", since = "1.1.0")] pub type ino_t = u64;