diff --git a/AMBuildScript b/AMBuildScript
index 95906b06..c71ed891 100644
--- a/AMBuildScript
+++ b/AMBuildScript
@@ -9,19 +9,18 @@ class SM:
 
 		#Build SDK info
 		self.sdkInfo = { }
-		self.sdkInfo['ep1'] =   {'sdk': 'HL2SDK',        'ext': '1.ep1',   'def': '1',
-		                         'name': 'EPISODEONE'}
-		self.sdkInfo['ep2'] =   {'sdk': 'HL2SDKOB',      'ext': '2.ep2',   'def': '3',
-		                         'name': 'ORANGEBOX'}
-		self.sdkInfo['ep2v'] =  {'sdk': 'HL2SDKOBVALVE', 'ext': '2.ep2v',  'def': '4',
-		                         'name': 'ORANGEBOXVALVE'}
-		self.sdkInfo['l4d'] =   {'sdk': 'HL2SDKL4D',     'ext': '2.l4d',   'def': '5',
-		                         'name': 'LEFT4DEAD'}
-		self.sdkInfo['l4d2'] =   {'sdk': 'HL2SDKL4D2',     'ext': '2.l4d2',   'def': '6',
-		                         'name': 'LEFT4DEAD2'}
-		if AMBuild.target['platform'] == 'windows':
-			self.sdkInfo['darkm'] = {'sdk': 'HL2SDK-DARKM',  'ext': '2.darkm', 'def': '2',
-		                           'name': 'DARKMESSIAH'}
+		self.sdkInfo['ep1'] =   {'sdk': 'HL2SDK',          'ext': '1.ep1',   'def': '1',
+		                         'name': 'EPISODEONE',     'platform': ['windows', 'linux']}
+		self.sdkInfo['ep2'] =   {'sdk': 'HL2SDKOB',        'ext': '2.ep2',   'def': '3',
+		                         'name': 'ORANGEBOX',      'platform': ['windows', 'linux']}
+		self.sdkInfo['ep2v'] =  {'sdk': 'HL2SDKOBVALVE',   'ext': '2.ep2v',  'def': '4',
+		                         'name': 'ORANGEBOXVALVE', 'platform': ['windows', 'linux', 'darwin']}
+		self.sdkInfo['l4d'] =   {'sdk': 'HL2SDKL4D',       'ext': '2.l4d',   'def': '5',
+		                         'name': 'LEFT4DEAD',      'platform': ['windows', 'linux']}
+		self.sdkInfo['l4d2'] =  {'sdk': 'HL2SDKL4D2',      'ext': '2.l4d2',  'def': '6',
+		                         'name': 'LEFT4DEAD2',     'platform': ['windows', 'linux']}
+		self.sdkInfo['darkm'] = {'sdk': 'HL2SDK-DARKM',    'ext': '2.darkm', 'def': '2',
+		                         'name': 'DARKMESSIAH',    'platform': ['windows']}
 
 		if AMBuild.mode == 'config':
 			#Detect compilers
@@ -29,14 +28,16 @@ class SM:
 
 			#Detect variables
 			envvars = { 'MMSOURCE18':    'mmsource-1.8',
-									'HL2SDK':        'hl2sdk',
-									'HL2SDKOB':      'hl2sdk-ob',
-									'HL2SDKL4D':     'hl2sdk-l4d',
 									'HL2SDKOBVALVE': 'hl2sdk-ob-valve',
-									'HL2SDKL4D2': 	 'hl2sdk-l4d2',
 									'MYSQL5':        'mysql-5.0'
 			}
 
+			if AMBuild.target['platform'] != 'darwin':
+				envvars['HL2SDK'] = 'hl2sdk'
+				envvars['HL2SDKOB'] = 'hl2sdk-ob'
+				envvars['HL2SDKL4D'] = 'hl2sdk-l4d'
+				envvars['HL2SDKL4D2'] = 'hl2sdk-l4d2'
+
 			#Dark Messiah is Windows-only
 			if AMBuild.target['platform'] == 'windows':
 				envvars['HL2SDK-DARKM'] = 'hl2sdk-darkm'
@@ -243,7 +244,6 @@ class SM:
 
 		info = self.sdkInfo
 		compiler['CDEFINES'].extend(['SE_' + info[i]['name'] + '=' + info[i]['def'] for i in info])
-		compiler['CDEFINES'].append('SE_DARKMESSIAH=2')
 
 		paths = [['public'], ['public', 'engine'], ['public', 'mathlib'], ['public', 'vstdlib'],
 						 ['public', 'tier0'], ['public', 'tier1']]
diff --git a/core/AMBuilder b/core/AMBuilder
index c66df50e..fdc3e386 100644
--- a/core/AMBuilder
+++ b/core/AMBuilder
@@ -3,6 +3,9 @@ import os
 
 for i in SM.sdkInfo:
 	sdk = SM.sdkInfo[i]
+	if AMBuild.target['platform'] not in sdk['platform']:
+		continue
+
 	name = 'sourcemod.' + sdk['ext']
 
 	compiler = SM.DefaultHL2Compiler('core', i)
diff --git a/extensions/bintools/AMBuilder b/extensions/bintools/AMBuilder
index 611006c2..b6e904ba 100644
--- a/extensions/bintools/AMBuilder
+++ b/extensions/bintools/AMBuilder
@@ -3,6 +3,9 @@ import os
 
 for i in SM.sdkInfo:
 	sdk = SM.sdkInfo[i]
+	if AMBuild.target['platform'] not in sdk['platform']:
+		continue
+
 	name = 'bintools.ext.' + sdk['ext']
 	
 	compiler = SM.DefaultHL2Compiler('extensions/bintools', i, True, '')
diff --git a/extensions/cstrike/AMBuilder b/extensions/cstrike/AMBuilder
index 89c33d19..fb6db61b 100644
--- a/extensions/cstrike/AMBuilder
+++ b/extensions/cstrike/AMBuilder
@@ -2,20 +2,22 @@
 import os
 
 sdk = SM.sdkInfo['ep1']
-compiler = SM.DefaultHL2Compiler('extensions/cstrike', 'ep1')
 
-name = 'game.cstrike.ext.' + sdk['ext']
-extension = AMBuild.AddJob(name)
-binary = Cpp.LibraryBuilder(name, AMBuild, extension, compiler)
-SM.PreSetupHL2Job(extension, binary, 'ep1')
-binary.AddSourceFiles('extensions/cstrike', [
-	'extension.cpp',
-	'natives.cpp',
-	'RegNatives.cpp',
-	'timeleft.cpp',
-	'sdk/smsdk_ext.cpp'
-	])
-SM.PostSetupHL2Job(extension, binary, 'ep1')
-SM.AutoVersion('extensions/cstrike', binary)
-binary.SendToJob()
+if AMBuild.target['platform'] in sdk['platform']:
+	compiler = SM.DefaultHL2Compiler('extensions/cstrike', 'ep1')
+
+	name = 'game.cstrike.ext.' + sdk['ext']
+	extension = AMBuild.AddJob(name)
+	binary = Cpp.LibraryBuilder(name, AMBuild, extension, compiler)
+	SM.PreSetupHL2Job(extension, binary, 'ep1')
+	binary.AddSourceFiles('extensions/cstrike', [
+		'extension.cpp',
+		'natives.cpp',
+		'RegNatives.cpp',
+		'timeleft.cpp',
+		'sdk/smsdk_ext.cpp'
+		])
+	SM.PostSetupHL2Job(extension, binary, 'ep1')
+	SM.AutoVersion('extensions/cstrike', binary)
+	binary.SendToJob()
 
diff --git a/extensions/sdktools/AMBuilder b/extensions/sdktools/AMBuilder
index dfda28df..e2c520b6 100644
--- a/extensions/sdktools/AMBuilder
+++ b/extensions/sdktools/AMBuilder
@@ -2,6 +2,10 @@
 import os
 
 for i in SM.sdkInfo:
+	sdk = SM.sdkInfo[i]
+	if AMBuild.target['platform'] not in sdk['platform']:
+		continue
+
 	compiler = SM.DefaultHL2Compiler('extensions/sdktools', i)
 	compiler['CXXINCLUDES'].append(os.path.join(AMBuild.sourceFolder, 'public', 'jit'))
 	compiler['CXXINCLUDES'].append(os.path.join(AMBuild.sourceFolder, 'public', 'jit', 'x86'))
@@ -9,7 +13,6 @@ for i in SM.sdkInfo:
 	if i != 'ep1':
 		compiler['CDEFINES'].append('HOOKING_ENABLED')
 
-	sdk = SM.sdkInfo[i]
 	name = 'sdktools.ext.' + sdk['ext']
 	extension = AMBuild.AddJob(name)
 	binary = Cpp.LibraryBuilder(name, AMBuild, extension, compiler)