fix build on 32bit systems

Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>

0001-Fix-read_u64-for-32-bit-platforms.patch

@@ -0,0 +1,50 @@
+From f578b5f3761f56cb5c5d74ae476006341a5c33c8 Mon Sep 17 00:00:00 2001
+From: Diggory Hardy <git@dhardy.name>
+Date: Sat, 25 Nov 2017 17:38:40 +0000
+Subject: [PATCH] Fix read_u64 for 32-bit platforms
+
+(Why you can't rely on .to_le() being correct I don't understand. If compiler
+is mixed-endian then to_le ought still do the correct swaps.)
+---
+ seahash/src/buffer.rs | 4 ++--
+ seahash/src/helper.rs | 2 +-
+ 2 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/seahash/src/buffer.rs b/seahash/src/buffer.rs
+index 573273d..eb2193c 100644
+--- a/seahash/src/buffer.rs
++++ b/seahash/src/buffer.rs
+@@ -63,7 +63,7 @@ impl State {
+ 
+             // Calculate the number of excessive bytes. These are bytes that could not be handled in
+             // the loop above.
+-            let mut excessive = buf.len() as usize + buf.as_ptr() as usize - end_ptr as usize;
++            let mut excessive = buf.len() % 32;
+             // Handle the excessive bytes.
+             match excessive {
+                 0 => {},
+@@ -71,7 +71,7 @@ impl State {
+                     // 1 or more excessive.
+ 
+                     // Write the last excessive bytes (<8 bytes).
+-                    a ^= helper::read_int(slice::from_raw_parts(ptr as *const u8, excessive));
++                    a ^= helper::read_int(slice::from_raw_parts(ptr, excessive));
+ 
+                     // Diffuse.
+                     a = helper::diffuse(a);
+diff --git a/seahash/src/helper.rs b/seahash/src/helper.rs
+index a95b89c..d3be89a 100644
+--- a/seahash/src/helper.rs
++++ b/seahash/src/helper.rs
+@@ -60,7 +60,7 @@ pub unsafe fn read_u64(ptr: *const u8) -> u64 {
+     {
+         // We cannot be sure about the memory layout of a potentially emulated 64-bit integer, so
+         // we read it manually. If possible, the compiler should emit proper instructions.
+-        (*(ptr as *const u32)).to_le() as u64 | ((*(ptr as *const u32)).to_le() as u64) << 32
++        (*(ptr as *const u32)).to_le() as u64 | ((*(ptr as *const u32).offset(1)).to_le() as u64) << 32
+     }
+ 
+     #[cfg(target_pointer_width = "64")]
+-- 
+2.16.2
+

rust-seahash.spec

@@ -13,6 +13,8 @@ Summary:        Blazingly fast, portable hash function with proven statistical g
 License:        MIT
 URL:            https://crates.io/crates/seahash
 Source0:        https://crates.io/api/v1/crates/%{crate}/%{version}/download#/%{crate}-%{version}.crate
+# https://github.com/redox-os/tfs/pull/74
+Patch0001:      0001-Fix-read_u64-for-32-bit-platforms.patch
 
 ExclusiveArch:  %{rust_arches}
 
@@ -32,7 +34,7 @@ This package contains library source intended for building other packages
 which use %{crate} from crates.io.
 
 %prep
-%autosetup -n %{crate}-%{version} -p1
+%autosetup -n %{crate}-%{version} -p2
 %cargo_prep
 
 %build