Update EnvironmentVariables.cpp

Author: compnerd

stdlib/public/runtime/EnvironmentVariables.cpp

@@ -248,6 +248,7 @@ SWIFT_END_DECLS
 
 namespace swift {
 namespace runtime {
+namespace environment {
 
 SWIFT_BEGIN_DECLS
 
@@ -270,3 +271,4 @@ SWIFT_END_DECLS
 
 }
 }
+}