Move over to ABSL logging and flags.

Removes gperftools too since that wants gflags.

Here come the fireworks.

Change-Id: I79cb7bcf60f1047fbfa28bfffc21a0fd692e4b1c
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/frc971/math/BUILD b/frc971/math/BUILD
index b8cd2fc..b4ce504 100644
--- a/frc971/math/BUILD
+++ b/frc971/math/BUILD
@@ -22,8 +22,9 @@
     deps = [
         ":matrix_fbs",
         "//aos:json_to_flatbuffer",
-        "@com_github_google_glog//:glog",
         "@com_github_tartanllama_expected",
+        "@com_google_absl//absl/log",
+        "@com_google_absl//absl/log:check",
         "@org_tuxfamily_eigen//:eigen",
     ],
 )
diff --git a/frc971/math/flatbuffers_matrix.h b/frc971/math/flatbuffers_matrix.h
index cfca897..356b4ec 100644
--- a/frc971/math/flatbuffers_matrix.h
+++ b/frc971/math/flatbuffers_matrix.h
@@ -3,7 +3,8 @@
 // This library provides utilities for converting between a frc971.fbs.Matrix
 // flatbuffer type and an Eigen::Matrix.
 // The interesting methods are ToEigen(), ToEigenOrDie(), and FromEigen().
-#include "glog/logging.h"
+#include "absl/log/check.h"
+#include "absl/log/log.h"
 #include "tl/expected.hpp"
 #include <Eigen/Core>