Opportunistically use perftools if installed.
Allows us to collect profiles of the open source build using gprof.
diff --git a/Makefile b/Makefile
index b43cb73..ab1ba14 100644
--- a/Makefile
+++ b/Makefile
@@ -172,6 +172,13 @@
OPENSSL_ALPN_CHECK_CMD = $(CC) $(CFLAGS) $(CPPFLAGS) -o /dev/null test/build/openssl-alpn.c -lssl -lcrypto -ldl $(LDFLAGS)
ZLIB_CHECK_CMD = $(CC) $(CFLAGS) $(CPPFLAGS) -o /dev/null test/build/zlib.c -lz $(LDFLAGS)
+PERFTOOLS_CHECK_CMD = $(CC) $(CFLAGS) $(CPPFLAGS) -o /dev/null test/build/perftools.c -lprofiler $(LDFLAGS)
+
+HAS_SYSTEM_PERFTOOLS = $(shell $(PERFTOOLS_CHECK_CMD) 2> /dev/null && echo true || echo false)
+ifeq ($(HAS_SYSTEM_PERFTOOLS),true)
+DEFINES += GRPC_HAVE_PERFTOOLS
+LIBS += profiler
+endif
ifndef REQUIRE_CUSTOM_LIBRARIES_$(CONFIG)
HAS_SYSTEM_OPENSSL_ALPN = $(shell $(OPENSSL_ALPN_CHECK_CMD) 2> /dev/null && echo true || echo false)