Fix build.

AMBuildScript

@@ -499,17 +499,16 @@ if SM.use_auto_versioning():
   )
 
 # Build SourcePawn externally.
-with builder.Context('sourcepawn') as context:
+SourcePawn = builder.RunScript('sourcepawn/AMBuildScript', {})
-  SourcePawn = builder.RunScript('sourcepawn/AMBuildScript', {})
+SP = SourcePawn(
-  SP = SourcePawn(
   root = SM,
   amtl = os.path.join(builder.sourcePath, 'public', 'amtl'),
-  )
+)
-  SP.BuildCore()
+SP.BuildCore()
-  SM.spcomp = SP.spcomp
+SM.spcomp = SP.spcomp
-  SM.binaries += [
+SM.binaries += [
   SP.libsourcepawn
-  ]
+]
 
 BuildScripts = [
   'loader/AMBuilder',