boost187: move cygwin patch to generic.nix

Since #472755, `boost187.override { patches = ...; }` does not work as expected.

pkgs/development/libraries/boost/1.87.nix

@@ -1,10 +1,4 @@
-{
-  lib,
-  stdenv,
-  callPackage,
-  fetchurl,
-  ...
-}@args:
+{ callPackage, fetchurl, ... }@args:
 
 callPackage ./generic.nix (
   args
@@ -21,7 +15,5 @@ callPackage ./generic.nix (
       # SHA256 from http://www.boost.org/users/history/version_1_87_0.html
       sha256 = "af57be25cb4c4f4b413ed692fe378affb4352ea50fbe294a11ef548f4d527d89";
     };
-
-    patches = lib.optional stdenv.hostPlatform.isCygwin ./Fix-cygwin-build-187.patch;
   }
 )

pkgs/development/libraries/boost/generic.nix

@@ -255,7 +255,10 @@ stdenv.mkDerivation {
         extraPrefix = "libs/context/";
         hash = "sha256-Z8uw2+4IEybqVcU25i/0XJKS16hi/+3MXUxs53ghjL0=";
       })
-    ];
+    ]
+    ++ lib.optional (
+      stdenv.hostPlatform.isCygwin && lib.versionAtLeast version "1.87" && lib.versionOlder version "1.88"
+    ) ./Fix-cygwin-build-187.patch;
 
   meta = {
     homepage = "http://boost.org/";