fix(fuzz): Make sanitizer flags optional

Currently OSS fuzz expects to have complete control over the
sanitizer flags. As we currently have these set it's causing
problems with the OSS fuzz build. Instead we should use the
provided variables from the OSS fuzz build environment. For
local testing we'll create a set a well defined defaults.

2 files changed, 12 insertions, 6 deletions

diff --git a/.github/workflows/pre-commit.yml b/.github/workflows/pre-commit.yml
index 8a1101ac0..d2150d13f 100644
--- a/.github/workflows/pre-commit.yml
+++ b/.github/workflows/pre-commit.yml
@@ -38,6 +38,8 @@ jobs:
 
     - name: Build Fuzzer
       run: |
+        export CC=clang
+        export CXX=clang++
         fuzz_harness=$(ls -d test/fuzz/device/*/)
         for h in $fuzz_harness
         do
diff --git a/test/fuzz/make.mk b/test/fuzz/make.mk
index 03254112f..6717ebc80 100644
--- a/test/fuzz/make.mk
+++ b/test/fuzz/make.mk
@@ -16,9 +16,9 @@ __check_defined = \
 
 #-------------- Fuzz harness compiler  ------------
 
-CC = clang
-CXX = clang++
-GDB = gdb
+CC ?= clang
+CXX ?= clang++
+GDB ?= gdb
 OBJCOPY = objcopy
 SIZE = size
 MKDIR = mkdir
@@ -34,6 +34,13 @@ else
   PYTHON = python3
 endif
 
+#-------------- Fuzz harness flags ------------
+COVERAGE_FLAGS ?= -fsanitize-coverage=trace-pc-guard
+SANITIZER_FLAGS ?= -fsanitize=fuzzer \
+                   -fsanitize=address
+
+CFLAGS += $(COVERAGE_FLAGS) $(SANITIZER_FLAGS)
+
 #-------------- Source files and compiler flags --------------
 
 
@@ -42,9 +49,6 @@ INC += $(TOP)/test
 # Compiler Flags
 CFLAGS += \
   -ggdb \
-  -fsanitize=fuzzer \
-  -fsanitize=address \
-  -fsanitize=undefined \
   -fdata-sections \
   -ffunction-sections \
   -fno-strict-aliasing \