Allow a build config called CONFIG=latprof that defines the appropriate
variables to set up the GRPC_LATENCY_PROFILER preprocessor macro so that timing
actually takes place.
diff --git a/Makefile b/Makefile
index f44833a..2b780b5 100644
--- a/Makefile
+++ b/Makefile
@@ -85,6 +85,15 @@
LDFLAGS_opt =
DEFINES_opt = NDEBUG
+VALID_CONFIG_latprof = 1
+CC_latprof = $(DEFAULT_CC)
+CXX_latprof = $(DEFAULT_CXX)
+LD_latprof = $(DEFAULT_CC)
+LDXX_latprof = $(DEFAULT_CXX)
+CPPFLAGS_latprof = -O2 -DGRPC_LATENCY_PROFILER
+LDFLAGS_latprof =
+DEFINES_latprof = NDEBUG
+
VALID_CONFIG_dbg = 1
CC_dbg = $(DEFAULT_CC)
CXX_dbg = $(DEFAULT_CXX)