5 files changed, 41 insertions, 4 deletions
diff --git a/src/engine/SCons/Builder.py b/src/engine/SCons/Builder.py
index 72b01cf..2852b3a 100644
--- a/src/engine/SCons/Builder.py
+++ b/src/engine/SCons/Builder.py
@@ -94,7 +94,20 @@ class CommandAction(ActionBase):
 	if print_actions:
 	    self.show(cmd)
 	if execute_actions:
-	    os.system(cmd)
+	    pid = os.fork()
+	    if not pid:
+		# Child process.
+		args = string.split(cmd)
+		try:
+		    ENV = kw['ENV']
+		except:
+		    import SCons.Defaults
+		    ENV = SCons.Defaults.ENV
+		os.execvpe(args[0], args, ENV)
+	    else:
+		# Parent process.
+		os.waitpid(pid, 0)
+
 
 class FunctionAction(ActionBase):
     """Class for Python function actions."""
diff --git a/src/engine/SCons/Defaults.py b/src/engine/SCons/Defaults.py
index 7b5e83d..0f6ffda 100644
--- a/src/engine/SCons/Defaults.py
+++ b/src/engine/SCons/Defaults.py
@@ -20,3 +20,5 @@ Program = SCons.Builder.Builder(name = 'Program',
 				action = 'cc -o %(target)s %(source)s')
 
 Builders = [Object, Program]
+
+ENV = { 'PATH' : '/usr/local/bin:/bin:/usr/bin' }
diff --git a/src/engine/SCons/Environment.py b/src/engine/SCons/Environment.py
index 508392b..c7c32dd 100644
--- a/src/engine/SCons/Environment.py
+++ b/src/engine/SCons/Environment.py
@@ -61,6 +61,9 @@ class Environment:
 	else:
 	    import SCons.Defaults
 	    kw['BUILDERS'] = SCons.Defaults.Builders[:]
+	if not kw.has_key('ENV'):
+	    import SCons.Defaults
+	    kw['ENV'] = SCons.Defaults.ENV.copy()
 	self._dict.update(copy.deepcopy(kw))
 
 	class BuilderWrapper:
@@ -74,8 +77,16 @@ class Environment:
 	    def __call__(self, target = None, source = None):
 		return self.builder(self.env, target, source)
 
+	    # This allows a Builder to be executed directly
+	    # through the Environment to which it's attached.
+	    # In practice, we shouldn't need this, because
+	    # builders actually get executed through a Node.
+	    # But we do have a unit test for this, and can't
+	    # yet rule out that it would be useful in the
+	    # future, so leave it for now.
 	    def execute(self, **kw):
-		apply(self.builder.execute, (), kw)
+	    	kw['env'] = self
+	    	apply(self.builder.execute, (), kw)
 
 	for b in kw['BUILDERS']:
 	    setattr(self, b.name, BuilderWrapper(self, b))
diff --git a/src/engine/SCons/EnvironmentTests.py b/src/engine/SCons/EnvironmentTests.py
index 0488173..c503fe2 100644
--- a/src/engine/SCons/EnvironmentTests.py
+++ b/src/engine/SCons/EnvironmentTests.py
@@ -16,7 +16,7 @@ class Builder:
     def __init__(self, name = None):
     	self.name = name
 
-    def execute(self, target = None, source = None):
+    def execute(self, target = None, **kw):
 	built_it[target] = 1
 
 
@@ -94,6 +94,16 @@ class EnvironmentTestCase(unittest.TestCase):
 	assert xxx == 'x'
 	assert zzz == 'z'
 	assert env.Dictionary().has_key('BUILDERS')
+	assert env.Dictionary().has_key('ENV')
+
+    def test_ENV(self):
+	"""Test setting the external ENV in Environments
+	"""
+	env = Environment()
+	assert env.Dictionary().has_key('ENV')
+
+	env = Environment(ENV = { 'PATH' : '/foo:/bar' })
+	assert env.Dictionary('ENV')['PATH'] == '/foo:/bar'
 
     def test_Environment(self):
 	"""Test construction Environments creation
diff --git a/src/engine/SCons/Node/__init__.py b/src/engine/SCons/Node/__init__.py
index 8609c57..4f414ec 100644
--- a/src/engine/SCons/Node/__init__.py
+++ b/src/engine/SCons/Node/__init__.py
@@ -25,7 +25,8 @@ class Node:
 
     def build(self):
 	sources_str = string.join(map(lambda x: str(x), self.sources))
-	self.builder.execute(target = str(self), source = sources_str)
+	self.builder.execute(ENV = self.env.Dictionary('ENV'),
+			     target = str(self), source = sources_str)
 
     def builder_set(self, builder):
 	self.builder = builder