target/m68k: Add semihosting stub

Since the SEMIHOSTING feature is optional, we need
a stub to link when it is disabled.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240717105723.58965-3-philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240718094523.1198645-10-alex.bennee@linaro.org>

target/m68k/meson.build

@@ -11,9 +11,12 @@ m68k_ss.add(files(
 
 m68k_system_ss = ss.source_set()
 m68k_system_ss.add(files(
-  'm68k-semi.c',
   'monitor.c'
 ))
+m68k_system_ss.add(when: ['CONFIG_SEMIHOSTING'],
+  if_true: files('m68k-semi.c'),
+  if_false: files('semihosting-stub.c')
+)
 
 target_arch += {'m68k': m68k_ss}
 target_system_arch += {'m68k': m68k_system_ss}

target/m68k/semihosting-stub.c

@@ -0,0 +1,15 @@
+/*
+ *  m68k/ColdFire semihosting stub
+ *
+ * SPDX-FileContributor: Philippe Mathieu-Daudé <philmd@linaro.org>
+ * SPDX-FileCopyrightText: 2024 Linaro Ltd.
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+
+void do_m68k_semihosting(CPUM68KState *env, int nr)
+{
+    g_assert_not_reached();
+}