MicroPython patch to output stdout to semihosting whenever USB-CDC is closed

rp2-semihosting-when-cdc-closed.patch

diff --git a/ports/rp2/CMakeLists.txt b/ports/rp2/CMakeLists.txt
index 8c8119e06..98c3de93d 100644
--- a/ports/rp2/CMakeLists.txt
+++ b/ports/rp2/CMakeLists.txt
@@ -92,6 +92,7 @@ set(MICROPY_SOURCE_LIB
     ${MICROPY_DIR}/shared/runtime/interrupt_char.c
     ${MICROPY_DIR}/shared/runtime/mpirq.c
     ${MICROPY_DIR}/shared/runtime/pyexec.c
+    ${MICROPY_DIR}/shared/runtime/semihosting.c
     ${MICROPY_DIR}/shared/runtime/stdout_helpers.c
     ${MICROPY_DIR}/shared/runtime/sys_stdio_mphal.c
     ${MICROPY_DIR}/shared/timeutils/timeutils.c
diff --git a/ports/rp2/main.c b/ports/rp2/main.c
index 0cf22bfec..28f330167 100644
--- a/ports/rp2/main.c
+++ b/ports/rp2/main.c
@@ -37,6 +37,7 @@
 #include "shared/readline/readline.h"
 #include "shared/runtime/gchelper.h"
 #include "shared/runtime/pyexec.h"
+#include "shared/runtime/semihosting.h"
 #include "tusb.h"
 #include "uart.h"
 #include "modmachine.h"
@@ -85,6 +86,8 @@ int main(int argc, char **argv) {
     mp_uart_init();
     #endif
 
+    mp_semihosting_init();
+
     #if MICROPY_HW_ENABLE_USBDEV
     bi_decl(bi_program_feature("USB REPL"))
     tusb_init();
diff --git a/ports/rp2/mphalport.c b/ports/rp2/mphalport.c
index 63ff76f5d..c88baac3f 100644
--- a/ports/rp2/mphalport.c
+++ b/ports/rp2/mphalport.c
@@ -146,6 +146,9 @@ void mp_hal_stdout_tx_strn(const char *str, mp_uint_t len) {
             tud_cdc_write_flush();
             i += n2;
         }
+    } else {
+        #include "shared/runtime/semihosting.h"
+        mp_semihosting_tx_strn(str, len);
     }
     #endif