fetchurl: switch to the usual curl

I verified that krb5 doesn't need yacc in lib-only build,
simplifying the circular-reference cut.

pkgs/development/libraries/kerberos/krb5.nix

@@ -22,9 +22,10 @@ stdenv.mkDerivation rec {
   configureFlags = [ "--with-tcl=no" "--localstatedir=/var/lib"]
     ++ optional stdenv.isFreeBSD ''WARN_CFLAGS=""'';
 
-  nativeBuildInputs = [ pkgconfig perl yacc ]
+  nativeBuildInputs = [ pkgconfig perl ]
+    ++ optional (!libOnly) yacc
     # Provides the mig command used by the build scripts
-    ++ optional stdenv.isDarwin bootstrap_cmds;
+    ++ optional (stdenv.isDarwin && !libOnly) bootstrap_cmds;
   buildInputs = [ openssl ]
     ++ optionals (!libOnly) [ openldap libedit ];
 

pkgs/top-level/all-packages.nix

@@ -179,8 +179,7 @@ with pkgs;
 
   # `fetchurl' downloads a file from the network.
   fetchurl = import ../build-support/fetchurl {
-    inherit stdenv;
-    curl = curl.override { gssSupport = false; };
+    inherit stdenv curl;
   };
 
   fetchRepoProject = callPackage ../build-support/fetchrepoproject { };
@@ -8760,7 +8759,10 @@ with pkgs;
   krb5Full = callPackage ../development/libraries/kerberos/krb5.nix {
     inherit (darwin) bootstrap_cmds;
   };
-  libkrb5 = krb5Full.override { type = "lib"; };
+  libkrb5 = krb5Full.override {
+    fetchurl = fetchurlBoot;
+    type = "lib";
+  };
 
   languageMachines = recurseIntoAttrs (import ../development/libraries/languagemachines/packages.nix { inherit callPackage; });