(libunwind_la_SOURCES_local): Mention mi/backtrace.c.

(Logical change 1.192)
diff --git a/src/Makefile.am b/src/Makefile.am
index 80015b1..64f439e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -51,6 +51,7 @@
 
 # List of arch-independent files needed by local-only library (libunwind):
 libunwind_la_SOURCES_local =						\
+	mi/backtrace.c							\
 	mi/dyn-cancel.c mi/dyn-info-list.c mi/dyn-register.c		\
 	mi/Ldyn-extract.c mi/Lfind_dynamic_proc_info.c			\
 	mi/Lget_accessors.c						\