https://bugs.gentoo.org/706942
--- a/peripherals/sim_5206.c
+++ b/peripherals/sim_5206.c
@@ -23,7 +23,7 @@ static struct _sim_register *sim_register_lookup_by_offset(s32 offset);
 static struct _sim_register *sim_register_lookup_by_name(char *name);
 static void sim_interrupt_assert(s16 number, s16 vector);
 static void sim_interrupt_withdraw(s16 number);
-struct _sim sim_data;
+static struct _sim sim_data;
 
 /* name, offset, width, read, write, resetvalue, description */
 static struct _sim_register sim_reg[] = {
--- a/peripherals/sim_5307.c
+++ b/peripherals/sim_5307.c
@@ -59,7 +59,7 @@ static struct _sim_register *sim_register_lookup_by_offset(s32 offset);
 static struct _sim_register *sim_register_lookup_by_name(char *name);
 static void sim_interrupt_assert(s16 number, s16 vector);
 static void sim_interrupt_withdraw(s16 number);
-struct _sim sim_data;
+static struct _sim sim_data;
 
 /* name, offset, width, read, write, resetvalue, description */
 static struct _sim_register sim_reg[] = {