Improved the CMakeLists.txt just slightly. Provided a default, weak-attributed main function into libdeepstate so that tests don't need to define them. The weak attribute means that any main function defined by libfuzzer will be a strong symbol and take over, so there won't be a conflict. Adjusted examples accordingly to omit now redundant conditionally-compiled main functions, as that leaked out too many underlying details.

src/lib/DeepState.c

@@ -618,4 +618,10 @@ void __stack_chk_fail(void) {
   __builtin_unreachable();
 }
 
+__attribute__((weak))
+int main(int argc, char *argv[]) {
+  DeepState_InitOptions(argc, argv);
+  return DeepState_Run();
+}
+
 DEEPSTATE_END_EXTERN_C

src/lib/Log.c

@@ -126,6 +126,14 @@ void DeepState_LogFormat(enum DeepState_LogLevel level,
   va_end(args);
 }
 
+#pragma clang diagnostic push
+#pragma GCC diagnostic ignored "-Wunknown-warning-option"
+/*#pragma clang diagnostic ignored "-Wbuiltin-declaration-mismatch"
+*/
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wbuiltin-declaration-mismatch"
+
 /* Override libc! */
 DEEPSTATE_NOINLINE
 int puts(const char *str) {
@@ -216,4 +224,7 @@ int __vfprintf_chk(int flag, FILE *file, const char *format, va_list args) {
   return 0;
 }
 
+#pragma clang diagnostic pop
+#pragma GCC diagnostic pop
+
 DEEPSTATE_END_EXTERN_C