[mac] Use the host platform's strip command

build/toolchain/mac/BUILD.gn

Index: build/toolchain/mac/BUILD.gn
diff --git a/build/toolchain/mac/BUILD.gn b/build/toolchain/mac/BUILD.gn
index c26364fdac74e79450c218b2a5067441986d66ab..307b7504820cf88d031534889a8a77afbc06fa0c 100644
--- a/build/toolchain/mac/BUILD.gn
+++ b/build/toolchain/mac/BUILD.gn
@@ -230,7 +230,7 @@ mac_toolchain("clang_x64") {
   cc = "${goma_prefix}$prefix/clang"
   cxx = "${goma_prefix}$prefix/clang++"
   ld = cxx
-  strip = "${prefix}/strip"
+  strip = "strip"
   is_clang = true
   sysroot_flags = "-isysroot $mac_sdk_path -mmacosx-version-min=$mac_sdk_min"
 }
@@ -244,7 +244,7 @@ mac_toolchain("clang_x86") {
   cc = "${goma_prefix}$prefix/clang"
   cxx = "${goma_prefix}$prefix/clang++"
   ld = cxx
-  strip = "${prefix}/strip"
+  strip = "strip"
   is_clang = true
   sysroot_flags = "-isysroot $mac_sdk_path -mmacosx-version-min=$mac_sdk_min"
 }