Fix string_to_num_test

The gyp files didn't actually try building it, so it didn't build.

Change-Id: I6b833dc8c5f8219029837cadc6c7c506d70b68b6
diff --git a/aos/common/util/string_to_num_test.cc b/aos/common/util/string_to_num_test.cc
index 705de42..df3897a 100644
--- a/aos/common/util/string_to_num_test.cc
+++ b/aos/common/util/string_to_num_test.cc
@@ -40,7 +40,7 @@
 
 TEST(StringToNumTest, FloatingPointTest) {
   double result;
-  ASSERT_TRUE(StringToNumber<double>(::std::string("3.1415927")));
+  ASSERT_TRUE(StringToNumber<double>(::std::string("3.1415927"), &result));
   EXPECT_EQ(result, 3.1415927);
 }
 
diff --git a/aos/externals/BUILD b/aos/externals/BUILD
new file mode 100644
index 0000000..bd7be3c
--- /dev/null
+++ b/aos/externals/BUILD
@@ -0,0 +1,35 @@
+_header_dirs = [
+  'forwpilib',
+  'allwpilib/wpilibc/wpilibC++/include',
+  'allwpilib/wpilibc/wpilibC++Devices/include',
+  'allwpilib/hal/include',
+  'allwpilib/hal/lib/Athena/FRC_FPGA_ChipObject',
+  'allwpilib/hal/lib/Athena',
+]
+
+cc_library(
+  name = 'wpilib',
+  visibility = ['//visibility:public'],
+  srcs = glob([
+    'allwpilib/wpilibc/wpilibC++/src/*.cpp',
+    'allwpilib/wpilibc/wpilibC++Devices/src/*.cpp',
+    'allwpilib/wpilibc/wpilibC++Devices/src/Internal/*.cpp',
+    'allwpilib/hal/lib/Athena/*.cpp',
+    'allwpilib/hal/lib/Athena/ctre/*.cpp',
+  ]) + [
+    'forwpilib/dma.cc',
+  ],
+  hdrs = glob([d + '/*.h' for d in _header_dirs]),
+  includes = _header_dirs,
+  linkopts = [
+    '-Lallwpilib/ni-libraries',
+    '-lpthread',
+    '-lFRC_NetworkCommunication',
+    '-lRoboRIO_FRC_ChipObject',
+    '-lNiFpgaLv',
+    '-lNiFpga',
+    '-lNiRioSrv',
+    '-lspi',
+    '-li2c',
+  ],
+)