silence glib log output during fuzzing on oss-fuzz

src/fe-fuzz/fe-common/core/Makefile.am

@@ -22,6 +22,7 @@ LDADD = \
 	$(FUZZER_LIBS)
 
 theme_load_fuzz_SOURCES = \
+        ../../null-logger.c \
         theme-load.c \
 	$(top_srcdir)/src/fe-text/module-formats.c
 

src/fe-fuzz/fe-common/core/meson.build

@@ -1,6 +1,7 @@
 # this file is part of irssi
 executable('theme-load-fuzz',
   files(
+    '../../null-logger.c',
     'theme-load.c',
     '../../../fe-text/module-formats.c',
   ),

src/fe-fuzz/fe-common/core/theme-load.c

@@ -29,6 +29,7 @@
 #include <irssi/src/fe-common/core/printtext.h>
 #include <irssi/src/irc/core/irc.h>
 #include <irssi/src/fe-common/core/themes.h>
+#include <irssi/src/fe-fuzz/null-logger.h>
 
 #include <stddef.h>
 #include <stdint.h>
@@ -38,6 +39,9 @@
 int LLVMFuzzerInitialize(int *argc, char ***argv) {
 	char *irssi_argv[] = {*argv[0], "--home", "/tmp/irssi", NULL};
 	int irssi_argc = sizeof(irssi_argv) / sizeof(char *) - 1;
+#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+	g_log_set_null_logger();
+#endif
 	core_register_options();
 	fe_common_core_register_options();
 	args_execute(irssi_argc, irssi_argv);