Add x86 stack unwinding support to libcorkscrew.

Change-Id: I1d4f4b11b4c8bf517b1dd07afccbedc41a84fd1b
diff --git a/libcorkscrew/Android.mk b/libcorkscrew/Android.mk
index 08432ef..df019c35 100644
--- a/libcorkscrew/Android.mk
+++ b/libcorkscrew/Android.mk
@@ -31,6 +31,12 @@
 LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH -DCORKSCREW_HAVE_LIBIBERTY
 LOCAL_LDFLAGS += -liberty
 endif
+ifeq ($(TARGET_ARCH),x86)
+LOCAL_SRC_FILES += \
+	arch-x86/backtrace-x86.c \
+	arch-x86/ptrace-x86.c
+LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH
+endif
 
 LOCAL_SHARED_LIBRARIES += libdl libcutils