[DEVOPS-293] Fix segfault in cryptonite

See upstream issue at haskell-crypto/cryptonite#193

default.nix

@@ -14,9 +14,6 @@ with pkgs.lib;
 with pkgs.haskell.lib;
 
 let
-  addConfigureFlags = flags: drv: overrideCabal drv (drv: {
-    configureFlags = flags;
-  });
   cardanoPkgs = ((import ./pkgs { inherit pkgs; }).override {
     overrides = self: super: {
       cardano-sl = overrideCabal super.cardano-sl (drv: {
@@ -68,8 +65,9 @@ let
         postPatch = ":";
       });
 
-      # Gold linker fixes
-      cryptonite = addConfigureFlags ["--ghc-option=-optl-pthread"] super.cryptonite;
+      # TODO: get rid of pthreads option once cryptonite 0.25 is released
+      # DEVOPS-293: https://github.com/haskell-crypto/cryptonite/issues/193
+      cryptonite = appendPatch (appendConfigureFlag super.cryptonite "--ghc-option=-optl-pthread") ./pkgs/cryptonite-segfault-blake.patch;
 
       # Darwin fixes upstreamed in nixpkgs commit 71bebd52547f4486816fd320bb3dc6314f139e67
       hinotify = if pkgs.stdenv.isDarwin then self.hfsevents else super.hinotify;

pkgs/cryptonite-segfault-blake.patch

@@ -0,0 +1,13 @@
+diff --git a/Crypto/Hash/Blake2b.hs b/Crypto/Hash/Blake2b.hs
+index c22c284..19c68ba 100644
+--- a/Crypto/Hash/Blake2b.hs
++++ b/Crypto/Hash/Blake2b.hs
+@@ -85,7 +85,7 @@ instance HashAlgorithm Blake2b_512 where
+ foreign import ccall unsafe "cryptonite_blake2b_init"
+     c_blake2b_init :: Ptr (Context a) -> Word32 -> IO ()
+
+-foreign import ccall "cryptonite_blake2b_update"
++foreign import ccall unsafe "cryptonite_blake2b_update"
+     c_blake2b_update :: Ptr (Context a) -> Ptr Word8 -> Word32 -> IO ()
+
+ foreign import ccall unsafe "cryptonite_blake2b_finalize"