buildMavenPackage: do not clobber env variables, use this to fix cryptomator env variables (#502063)

pkgs/by-name/cr/cryptomator/package.nix

@@ -35,12 +35,11 @@ maven.buildMavenPackage rec {
   mvnParameters = "-Dmaven.test.skip=true -Plinux";
   mvnHash = "sha256-IVOcDFW5YKgUHJKX3ZXYVnOevwmOwN5yEU8jfPtCY1I=";
   mvnFetchExtraArgs.env = {
-    inherit SOURCE_DATE_EPOCH;
+    inherit (env) SOURCE_DATE_EPOCH;
   };
 
   # fix for "date 1980-01-01T00:00:00Z is not within the valid range 1980-01-01T00:00:02Z to 2099-12-31T23:59:59Z"
-  # this should be in env, but looks like buildMavenPackage doesn't support that
-  SOURCE_DATE_EPOCH = 315532802; # 1980-01-01T00:00:02Z
+  env.SOURCE_DATE_EPOCH = 315532802; # 1980-01-01T00:00:02Z
 
   preBuild = ''
     VERSION=${version}

pkgs/by-name/ma/maven/build-maven-package.nix

@@ -52,7 +52,9 @@ let
       ]
       ++ args.nativeBuildInputs or [ ];
 
-      env.JAVA_HOME = mvnJdk;
+      env = mvnFetchExtraArgs.env or { } // {
+        JAVA_HOME = mvnJdk;
+      };
 
       impureEnvVars = lib.fetchers.proxyImpureEnvVars;
 
@@ -119,7 +121,7 @@ let
       outputHashMode = "recursive";
       outputHash = mvnHash;
     }
-    // mvnFetchExtraArgs
+    // (removeAttrs mvnFetchExtraArgs [ "env" ])
   );
 in
 stdenv.mkDerivation (
@@ -131,7 +133,9 @@ stdenv.mkDerivation (
       maven
     ];
 
-    env.JAVA_HOME = mvnJdk;
+    env = args.env or { } // {
+      JAVA_HOME = mvnJdk;
+    };
 
     buildPhase = ''
       runHook preBuild