diff --git a/lib/rscons/application.rb b/lib/rscons/application.rb
index 25a811c..cdbfb84 100644
--- a/lib/rscons/application.rb
+++ b/lib/rscons/application.rb
@@ -82,6 +82,8 @@ module Rscons
     #
     # @return [void]
     def configure
+      cache = Cache.instance
+      cache.configuration_data = {}
       if project_name = @script.project_name
         Ansi.write($stdout, "Configuring ", :cyan, project_name, :reset, "...\n")
       else
@@ -96,10 +98,8 @@ module Rscons
         rv = 1
       end
       co.close
-      cache = Cache.instance
       cache.set_configured(rv == 0)
-      cache.set_default_environment_vars(@default_environment.to_h)
-      cache.write
+      cache.write!
       rv
     end
 
diff --git a/lib/rscons/cache.rb b/lib/rscons/cache.rb
index d254a37..0ad1949 100644
--- a/lib/rscons/cache.rb
+++ b/lib/rscons/cache.rb
@@ -104,27 +104,21 @@ module Rscons
       @dirty = true
     end
 
-    # Get the default environment construction variables.
-    #
-    # @return [Hash]
-    #   Default environment construction variables.
-    def get_default_environment_vars
-      @cache["default_environment_vars"]
+    # Access configuration data.
+    def configuration_data
+      @cache["configuration_data"]
     end
 
-    # Set the default environment construction variables.
+    # Set configuration data.
     #
-    # @param vars [Hash]
-    #   Default environment construction variables.
-    #
-    # @return [void]
-    def set_default_environment_vars(vars)
-      validate_json_object(vars)
-      @cache["default_environment_vars"] = vars
+    # @param value [Hash]
+    #   Configuration data.
+    def configuration_data=(value)
+      @cache["configuration_data"] = value
       @dirty = true
     end
 
-    # Write the cache to disk to be loaded next time.
+    # Write the cache to disk if it is dirty.
     #
     # @return [void]
     def write
@@ -137,6 +131,14 @@ module Rscons
       @dirty = false
     end
 
+    # Force a write of the cache to disk.
+    #
+    # @return [void]
+    def write!
+      @dirty = true
+      write
+    end
+
     # Check if target(s) are up to date.
     #
     # @param targets [Symbol, String, Array<String>]
@@ -354,6 +356,7 @@ module Rscons
       @cache["targets"] ||= {}
       @cache["directories"] ||= {}
       @cache["default_environment_vars"] ||= {}
+      @cache["configuration_data"] ||= {}
       @lookup_checksums = {}
       @dirty = false
     end