Index: rts/build/scons/filelist.py
===================================================================
--- rts/build/scons/filelist.py	(revision 3948)
+++ rts/build/scons/filelist.py	(working copy)
@@ -120,19 +120,16 @@
 
 
 def get_globalAI_source(env, which):
-	engine_files = []
-	if which == 'KAI-0.22':
-		engine_files += get_source(env, 'rts/System/creg') + ['rts/System/float3.cpp']
-	return get_AI_source(env, 'AI/Global', which) + engine_files
+	return get_AI_source(env, 'AI/Global', which)
 
 
 def get_groupAI_source(env, which):
-	engine_files = []
-	if which == 'EconomyAI' or which == 'MexUpgraderAI':
-		engine_files += get_source(env, 'rts/System/creg') + ['rts/System/float3.cpp']
-	return get_AI_source(env, 'AI/Group', which) + engine_files
+	return get_AI_source(env, 'AI/Group', which)
 
 
+def get_shared_AI_source(env):
+	return get_source(env, 'rts/System/creg') + ['rts/System/float3.cpp']
+
 def list_AIs(env, path, exclude_list = (), exclude_regexp = '^\.'):
 	exclude = re.compile(exclude_regexp)
 	files = os.listdir(path)
Index: SConstruct
===================================================================
--- SConstruct	(revision 3948)
+++ SConstruct	(working copy)
@@ -149,9 +149,19 @@
 # Use subst() to substitute $installprefix in datadir.
 install_dir = os.path.join(aienv['installprefix'], aienv['libdir'], 'AI/Helper-libs')
 
+# store shared ai objects so newer scons versions don't choke with
+# *** Two environments with different actions were specified for the same target
+aiobjs = []
+for f in filelist.get_shared_AI_source(aienv):
+        while isinstance(f, list):
+                f = f[0]
+        fpath, fbase = os.path.split(f)
+        fname, fext = fbase.rsplit('.', 1)
+        aiobjs.append(aienv.Object(os.path.join(fpath, fname + '-ai'), f))
+
 #Build GroupAIs
 for f in filelist.list_groupAIs(aienv, exclude_list=['build']):
-	lib = aienv.SharedLibrary(os.path.join('game/AI/Helper-libs', f), filelist.get_groupAI_source(aienv, f))
+	lib = aienv.SharedLibrary(os.path.join('game/AI/Helper-libs', f), aiobjs + filelist.get_groupAI_source(aienv, f))
 	Alias(f, lib)         # Allow e.g. `scons CentralBuildAI' to compile just an AI.
 	Alias('GroupAI', lib) # Allow `scons GroupAI' to compile all groupAIs.
 	Default(lib)
@@ -166,7 +176,7 @@
 
 #Build GlobalAIs
 for f in filelist.list_globalAIs(aienv, exclude_list=['build', 'CSAI', 'TestABICAI','AbicWrappersTestAI']):
-	lib = aienv.SharedLibrary(os.path.join('game/AI/Bot-libs', f), filelist.get_globalAI_source(aienv, f))
+	lib = aienv.SharedLibrary(os.path.join('game/AI/Bot-libs', f), aiobjs + filelist.get_globalAI_source(aienv, f))
 	Alias(f, lib)          # Allow e.g. `scons JCAI' to compile just a global AI.
 	Alias('GlobalAI', lib) # Allow `scons GlobalAI' to compile all globalAIs.
 	Default(lib)