Switch from 8bit-counters to trace-pc-guard.

Otherwise clang complains about:

  clang: error: argument '-fsanitize-coverage=8bit-counters' is
  deprecated, use '-fsanitize-coverage=trace-pc-guard' instead
  [-Werror,-Wdeprecated]

Change-Id: Icb2a8f874734040df6a2d39a62f8e946b366bfca
Reviewed-on: https://boringssl-review.googlesource.com/16128
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 167a8fe..c421e88 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -147,8 +147,8 @@
     set(RUNNER_ARGS ${RUNNER_ARGS} "-fuzzer" "-shim-config" "fuzzer_mode.json")
   endif()
 
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=address -fsanitize-coverage=edge,indirect-calls,8bit-counters")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=address -fsanitize-coverage=edge,indirect-calls,8bit-counters")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=address -fsanitize-coverage=edge,indirect-calls,trace-pc-guard")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=address -fsanitize-coverage=edge,indirect-calls,trace-pc-guard")
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_C_FLAGS} -fsanitize=address")
   link_directories(.)
 endif()