Revert "Ensure environment dependencies are correct"

This reverts commit e78473c33c.

Reason for revert: Broke mac builds, which rely on $PATH to find xcrun

Change-Id: I58711b94d472ab828823afaf53394a1aa869f3f5

android/config.go

@@ -289,7 +289,7 @@ func (c *config) Getenv(key string) string {
 		if c.envFrozen {
 			panic("Cannot access new environment variables after envdeps are frozen")
 		}
-		val, _ = originalEnv[key]
+		val = os.Getenv(key)
 		c.envDeps[key] = val
 	}
 	return val

android/env.go

@@ -15,9 +15,6 @@
 package android
 
 import (
-	"os"
-	"strings"
-
 	"android/soong/env"
 
 	"github.com/google/blueprint"
@@ -30,19 +27,6 @@ import (
 // compare the contents of the environment variables, rewriting the file if necessary to cause
 // a manifest regeneration.
 
-var originalEnv map[string]string
-
-func init() {
-	originalEnv = make(map[string]string)
-	for _, env := range os.Environ() {
-		idx := strings.IndexRune(env, '=')
-		if idx != -1 {
-			originalEnv[env[:idx]] = env[idx+1:]
-		}
-	}
-	os.Clearenv()
-}
-
 func EnvSingleton() blueprint.Singleton {
 	return &envSingleton{}
 }