Add support for building code for Debian armhf

I think this will work with the Ubuntu-based distribution on the TK1
too.

Change-Id: I62350d2f7a8914fb13c421be427388c6e46c5481
diff --git a/third_party/gperftools/BUILD b/third_party/gperftools/BUILD
index 8807e6c..ada8712 100644
--- a/third_party/gperftools/BUILD
+++ b/third_party/gperftools/BUILD
@@ -97,7 +97,7 @@
     '-DPRIuS=\\"lu\\"',
     '-DPRIxS=\\"lx\\"',
   ],
-  'roborio': [
+  'arm': [
     '-DPC_FROM_UCONTEXT=uc_mcontext.arm_pc',
     '-DPRIdS=\\"d\\"',
     '-DPRIuS=\\"u\\"',