tests: Allow for using non-default fuzzing initialization

src/test/fuzz/fuzz.cpp

@@ -22,7 +22,9 @@ static bool read_stdin(std::vector<uint8_t>& data)
     return length == 0;
 }
 
-static void initialize()
+// Default initialization: Override using a non-weak initialize().
+__attribute__((weak))
+void initialize()
 {
     const static auto verify_handle = MakeUnique<ECCVerifyHandle>();
 }

src/test/fuzz/fuzz.h

@@ -8,7 +8,7 @@
 #include <stdint.h>
 #include <vector>
 
-
+void initialize();
 void test_one_input(const std::vector<uint8_t>& buffer);
 
 #endif // BITCOIN_TEST_FUZZ_FUZZ_H