go: add disabled flag for packages

pkgs/development/go-modules/generic/default.nix

@@ -2,6 +2,9 @@
 
 { name, buildInputs ? []
 
+# Disabled flag
+, disabled ? false
+
 # Go import path of the package
 , goPackagePath
 
@@ -15,6 +18,8 @@
 
 , meta ? {}, ... } @ args':
 
+if disabled then throw "${name} not supported for go ${go.meta.branch}" else
+
 let
   args = lib.filterAttrs (name: _: name != "extraSrcs") args';
 in