Fix gdbserver location for build system.

The build system has to know where gdbserver is to copy it into the
app's lib directory.

Change-Id: I36d46e58cdeb1aab5713bba933b333b4950ec70c
diff --git a/build/core/setup-toolchain.mk b/build/core/setup-toolchain.mk
index ca5a3cd..3e2cc93 100644
--- a/build/core/setup-toolchain.mk
+++ b/build/core/setup-toolchain.mk
@@ -143,7 +143,7 @@
 TOOLCHAIN_PREFIX := $(TOOLCHAIN_PREBUILT_ROOT)/bin/$(TOOLCHAIN_PREFIX)
 
 # We expect the gdbserver binary for this toolchain to be located at its root.
-TARGET_GDBSERVER := $(NDK_ROOT)/prebuilt/android-$(TARGET_ARCH)/gdbserver/gdbserver
+TARGET_GDBSERVER := $(NDK_ROOT)/gdbserver/$(TARGET_ARCH)/gdbserver
 
 # compute NDK_APP_DST_DIR as the destination directory for the generated files
 NDK_APP_DST_DIR := $(NDK_APP_LIBS_OUT)/$(TARGET_ARCH_ABI)