Do not add non-existing -Bprebuilts/gcc/.../bin

* Only prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/x86_64-w64-mingw32/bin
  exists for x86_windows_host.
* Remove config.ToolPath;
  add required -B flags into ToolchainCflags and ToolchainLdflags.

Bug: 218883919
Test: make droid tidy-soong_subset
Change-Id: I9a18bf8cc0cf84e091c7463b3bda316eaab53aa3
diff --git a/cc/config/darwin_host.go b/cc/config/darwin_host.go
index 206bec1..5e3f7c7 100644
--- a/cc/config/darwin_host.go
+++ b/cc/config/darwin_host.go
@@ -258,8 +258,12 @@
 	return darwinAvailableLibraries
 }
 
-func (t *toolchainDarwin) ToolPath() string {
-	return "${config.MacToolPath}"
+func (t *toolchainDarwin) ToolchainCflags() string {
+	return "-B${config.MacToolPath}"
+}
+
+func (t *toolchainDarwin) ToolchainLdflags() string {
+	return "-B${config.MacToolPath}"
 }
 
 var toolchainDarwinArmSingleton Toolchain = &toolchainDarwinArm{}
diff --git a/cc/config/toolchain.go b/cc/config/toolchain.go
index 6320dbb..6cede11 100644
--- a/cc/config/toolchain.go
+++ b/cc/config/toolchain.go
@@ -16,7 +16,6 @@
 
 import (
 	"fmt"
-	"path/filepath"
 
 	"android/soong/android"
 )
@@ -77,7 +76,6 @@
 	GccTriple() string
 	// GccVersion should return a real value, not a ninja reference
 	GccVersion() string
-	ToolPath() string
 
 	IncludeFlags() string
 
@@ -198,10 +196,6 @@
 	return false
 }
 
-func (t toolchainBase) ToolPath() string {
-	return ""
-}
-
 type toolchain64Bit struct {
 	toolchainBase
 }
@@ -283,11 +277,4 @@
 	return LibclangRuntimeLibrary(t, "fuzzer")
 }
 
-func ToolPath(t Toolchain) string {
-	if p := t.ToolPath(); p != "" {
-		return p
-	}
-	return filepath.Join(t.GccRoot(), t.GccTriple(), "bin")
-}
-
 var inList = android.InList
diff --git a/cc/config/x86_windows_host.go b/cc/config/x86_windows_host.go
index 9daf40f..2c83211 100644
--- a/cc/config/x86_windows_host.go
+++ b/cc/config/x86_windows_host.go
@@ -15,6 +15,7 @@
 package config
 
 import (
+	"path/filepath"
 	"strings"
 
 	"android/soong/android"
@@ -180,6 +181,14 @@
 	return "${config.WindowsGccTriple}"
 }
 
+func (t *toolchainWindows) ToolchainCflags() string {
+	return "-B" + filepath.Join(t.GccRoot(), t.GccTriple(), "bin")
+}
+
+func (t *toolchainWindows) ToolchainLdflags() string {
+	return "-B" + filepath.Join(t.GccRoot(), t.GccTriple(), "bin")
+}
+
 func (t *toolchainWindows) GccVersion() string {
 	return windowsGccVersion
 }