Fix MIPS build.

Change-Id: I4863f21f3c2fd597ea36cb7096fc72db808643a3
diff --git a/libc/Android.mk b/libc/Android.mk
index d21878a..0f61bcf 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -494,7 +494,7 @@
 	bionic/ptrace.c
 
 libc_static_common_src_files += \
-    bionic/pthread.c
+    bionic/pthread.c \
     bionic/pthread_key.cpp \
 
 libc_arch_static_src_files := \