Include libpcre if present

Change-Id: I51bdabbd5b2c2263f3f72cdd2ffcba2bc97e0c43
diff --git a/prebuilt/Android.mk b/prebuilt/Android.mk
index bfa4ebd..305aa23 100644
--- a/prebuilt/Android.mk
+++ b/prebuilt/Android.mk
@@ -156,6 +156,9 @@
 ifneq ($(TW_RECOVERY_ADDITIONAL_RELINK_FILES),)
     RELINK_SOURCE_FILES += $(TW_RECOVERY_ADDITIONAL_RELINK_FILES)
 endif
+ifneq ($(wildcard external/pcre/Android.mk),)
+    RELINK_SOURCE_FILES += $(TARGET_OUT_SHARED_LIBRARIES)/libpcre.so
+endif
 
 TWRP_AUTOGEN := $(intermediates)/teamwin