fuzz: control debuglevel from Makefile

and make the compilation faster

tests/fuzz/Makefile

@@ -257,7 +257,7 @@ corpora: $(patsubst %,corpora/%,$(FUZZ_TARGETS))
 seedcorpora: $(patsubst %,corpora/%_seed_corpus.zip,$(FUZZ_TARGETS))
 
 regressiontest: corpora
-	CC="$(CC)" CXX="$(CXX)" CFLAGS="$(CFLAGS)" CXXFLAGS="$(CXXFLAGS)" LDFLAGS="$(LDFLAGS)" $(PYTHON) ./fuzz.py build all
+	CC="$(CC)" CXX="$(CXX)" CFLAGS="$(CFLAGS)" CXXFLAGS="$(CXXFLAGS)" LDFLAGS="$(LDFLAGS)" $(PYTHON) ./fuzz.py build all --debug=$(DEBUGLEVEL)
 	$(PYTHON) ./fuzz.py regression all
 
 clean:

tests/fuzz/fuzz.py

@@ -492,6 +492,7 @@ def build(args):
     subprocess.check_call(clean_cmd)
     build_cmd = [
         'make',
+        '-j',
         cc_str,
         cxx_str,
         cppflags_str,