pass flags through for oss-fuzz

tests-fuzz/Makefile.am

@@ -19,7 +19,18 @@ packet_libfuzzer_LDADD = $(top_builddir)/src/libknot.la
 zscanner_libfuzzer_SOURCES = zscanner_libfuzzer.c
 zscanner_libfuzzer_LDADD = $(top_builddir)/src/zscanner/libzscanner.la
 
+if OSS_FUZZ
+
+# CFLAGS, LDFLAGS, etc. are defined by the oss-fuzz environment; just link
+# in the fuzzing engine
+
+packet_libfuzzer_LDADD += ${LIB_FUZZING_ENGINE} -lc++
+zscanner_libfuzzer_LDADD += ${LIB_FUZZING_ENGINE} -lc++
+
+else
+
 if SANITIZE_FUZZER
+
 packet_libfuzzer_LDFLAGS = -fsanitize=fuzzer
 zscanner_libfuzzer_LDFLAGS = -fsanitize=fuzzer
 
@@ -28,14 +39,13 @@ zscanner_libfuzzer_LDFLAGS = -fsanitize=fuzzer
 TESTS = check/check_fuzzers.test
 EXTRA_DIST = check/check_fuzzers.test
 
-if OSS_FUZZ
-packet_libfuzzer_LDADD += -lFuzzingEngine
-zscanner_libfuzzer_LDADD += -lFuzzingEngine
-endif
-
 else
+
 packet_libfuzzer_SOURCES += main.c
 zscanner_libfuzzer_SOURCES += main.c
 AM_CPPFLAGS += -DTEST_RUN
 TESTS = $(FUZZERS)
-endif
+
+endif # if SANITIZE_FUZZER
+
+endif # if OSS_FUZZ