Fix our missing abs/labs/llabs/imaxabs (and imaxdiv) symbols.

Change-Id: I94c411c22634e43184445c82e7388e51fc46a8cc
diff --git a/libc/Android.mk b/libc/Android.mk
index db97a74..5f399b4 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -283,7 +283,12 @@
     upstream-freebsd/lib/libc/stdio/tempnam.c \
     upstream-freebsd/lib/libc/stdio/tmpnam.c \
     upstream-freebsd/lib/libc/stdio/wsetup.c \
+    upstream-freebsd/lib/libc/stdlib/abs.c \
     upstream-freebsd/lib/libc/stdlib/getopt_long.c \
+    upstream-freebsd/lib/libc/stdlib/imaxabs.c \
+    upstream-freebsd/lib/libc/stdlib/imaxdiv.c \
+    upstream-freebsd/lib/libc/stdlib/labs.c \
+    upstream-freebsd/lib/libc/stdlib/llabs.c \
     upstream-freebsd/lib/libc/stdlib/qsort.c \
     upstream-freebsd/lib/libc/stdlib/realpath.c \
     upstream-freebsd/lib/libc/string/wcpcpy.c \