ffs was not being built for x86.

Change-Id: I53e92273664a4d0a13536c2fa1aeb87e1f3cf4e8
diff --git a/libc/Android.mk b/libc/Android.mk
index 606fda2..4130e25 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -408,31 +408,32 @@
 
 ifeq ($(TARGET_ARCH),x86)
 libc_common_src_files += \
-	arch-x86/bionic/__get_sp.S \
-	arch-x86/bionic/__get_tls.c \
-	arch-x86/bionic/__set_tls.c \
-	arch-x86/bionic/clone.S \
-	arch-x86/bionic/_exit_with_stack_teardown.S \
-	arch-x86/bionic/futex_x86.S \
-	arch-x86/bionic/setjmp.S \
-	arch-x86/bionic/_setjmp.S \
-	arch-x86/bionic/sigsetjmp.S \
-	arch-x86/bionic/vfork.S \
-	arch-x86/bionic/syscall.S \
-	arch-x86/string/bcopy_wrapper.S \
-	arch-x86/string/memcpy_wrapper.S \
-	arch-x86/string/memmove_wrapper.S \
-	arch-x86/string/bzero_wrapper.S \
-	arch-x86/string/memcmp_wrapper.S \
-	arch-x86/string/memset_wrapper.S \
-	arch-x86/string/strcmp_wrapper.S \
-	arch-x86/string/strncmp_wrapper.S \
-	arch-x86/string/strlen_wrapper.S \
-	string/strcpy.c \
-	bionic/pthread-atfork.c \
-	bionic/pthread-rwlocks.c \
-	bionic/pthread-timers.c \
-	bionic/ptrace.c
+    arch-x86/bionic/clone.S \
+    arch-x86/bionic/_exit_with_stack_teardown.S \
+    arch-x86/bionic/futex_x86.S \
+    arch-x86/bionic/__get_sp.S \
+    arch-x86/bionic/__get_tls.c \
+    arch-x86/bionic/_setjmp.S \
+    arch-x86/bionic/setjmp.S \
+    arch-x86/bionic/__set_tls.c \
+    arch-x86/bionic/sigsetjmp.S \
+    arch-x86/bionic/syscall.S \
+    arch-x86/bionic/vfork.S \
+    arch-x86/string/bcopy_wrapper.S \
+    arch-x86/string/bzero_wrapper.S \
+    arch-x86/string/ffs.S \
+    arch-x86/string/memcmp_wrapper.S \
+    arch-x86/string/memcpy_wrapper.S \
+    arch-x86/string/memmove_wrapper.S \
+    arch-x86/string/memset_wrapper.S \
+    arch-x86/string/strcmp_wrapper.S \
+    arch-x86/string/strlen_wrapper.S \
+    arch-x86/string/strncmp_wrapper.S \
+    bionic/pthread-atfork.c \
+    bionic/pthread-rwlocks.c \
+    bionic/pthread-timers.c \
+    bionic/ptrace.c \
+    string/strcpy.c \
 
 libc_static_common_src_files += \
     bionic/pthread.c \
diff --git a/libc/arch-x86/string/fss.S b/libc/arch-x86/string/ffs.S
similarity index 100%
rename from libc/arch-x86/string/fss.S
rename to libc/arch-x86/string/ffs.S