Do not cache Waf tools in configure

ChangeLog

@@ -9,6 +9,7 @@ NEW IN WAF 1.9
   - Change cflags in the beginning / cppflags at the end #1505
   - Merge ${FOO}${BAR} flags in commands executed without a shell (no space added)
   - Interpret empty command-line defines as integer values #1704
+  - Waf tools are not cached on "waf configure" by default anymore; pass conf.load(.., cache=True)
 
 * Performance highlights:
   - Reduce the key size in bld.task_sigs by adding bld.node_sigs and bld.imp_sigs
@@ -27,4 +28,3 @@ NEW IN WAF 1.9
   - Modify Utils.run_once so that it accepts a list of *args
   - Improve the task consumer in Runner.py
 
-

TODO

@@ -1,7 +1,6 @@
 Waf 1.9
 -------
 
-* Do not cache waf tool detection
 * Fix the vala detection
 * Better consistency between check_cfg and check_cc variables
 * Let more context commands depend on the configuration

waflib/Configure.py

@@ -228,7 +228,7 @@ class ConfigurationContext(Context.Context):
 			tmpenv = self.all_envs[key]
 			tmpenv.store(os.path.join(self.cachedir.abspath(), key + Build.CACHE_SUFFIX))
 
-	def load(self, input, tooldir=None, funs=None, with_sys_path=True):
+	def load(self, input, tooldir=None, funs=None, with_sys_path=True, cache=False):
 		"""
 		Load Waf tools, which will be imported whenever a build is started.
 
@@ -238,6 +238,8 @@ class ConfigurationContext(Context.Context):
 		:type tooldir: list of string
 		:param funs: functions to execute from the waf tools
 		:type funs: list of string
+		:param cache: whether to prevent the tool from running twice
+		:type cache: bool
 		"""
 
 		tools = Utils.to_list(input)
@@ -246,6 +248,7 @@ class ConfigurationContext(Context.Context):
 			# avoid loading the same tool more than once with the same functions
 			# used by composite projects
 
+			if cache:
 				mag = (tool, id(self.env), tooldir, funs)
 				if mag in self.tool_cache:
 					self.to_log('(tool %s is already loaded, skipping)' % tool)