DO NOT MERGE - add sincos.c to libm compilation

For some reason, a previous backport from master didn't get this.

Change-Id: I59eb96ad9de495a659808fdfb557033476c3d123
diff --git a/libm/Android.mk b/libm/Android.mk
index fa73aff..28e8f33 100644
--- a/libm/Android.mk
+++ b/libm/Android.mk
@@ -3,6 +3,7 @@
 libm_common_src_files:= \
 	isinf.c  \
 	fpclassify.c \
+	sincos.c \
 	bsdsrc/b_exp.c \
 	bsdsrc/b_log.c \
 	bsdsrc/b_tgamma.c \