Remove Segger RTT from pico-btstack (#1995)

* Remove btstack Segger RTT from pico-btstack

We now have this in the SDK so adding it again in pico-btstack leads to
link errors.

But it's possible to use the btstack RTT functionality by defining
ENABLE_SEGGER_RTT=1, and if we're not using pico_stio_rtt we still need
to add the btstack RTT source.

* Fix build issues when RTT is enabled

Fixes raspberrypi/pico-examples#565

src/rp2_common/pico_btstack/CMakeLists.txt

@@ -28,7 +28,6 @@ if (EXISTS ${PICO_BTSTACK_PATH}/${BTSTACK_TEST_PATH})
     target_sources(pico_btstack_base INTERFACE
         ${PICO_BTSTACK_PATH}/3rd-party/micro-ecc/uECC.c
         ${PICO_BTSTACK_PATH}/3rd-party/rijndael/rijndael.c
-        ${PICO_BTSTACK_PATH}/3rd-party/segger-rtt/SEGGER_RTT.c
         ${PICO_BTSTACK_PATH}/3rd-party/segger-rtt/SEGGER_RTT_printf.c
         ${PICO_BTSTACK_PATH}/platform/embedded/btstack_tlv_flash_bank.c
         ${PICO_BTSTACK_PATH}/platform/embedded/hci_dump_embedded_stdout.c
@@ -60,6 +59,13 @@ if (EXISTS ${PICO_BTSTACK_PATH}/${BTSTACK_TEST_PATH})
         ${PICO_BTSTACK_PATH}/3rd-party/yxml/yxml.c
         ${CMAKE_CURRENT_LIST_DIR}/btstack_stdin_pico.c
     )
+    # pico-sdk now supports RTT using pico_enable_stdio_rtt in your cmake file or -DPICO_STDIO_RTT=1 on the command line
+    # Then the output of printf goes to RTT. But if you define ENABLE_SEGGER_RTT=1 it will use the btstack functionality to use RTT
+    # and we'll have to add the source file it requires.
+    target_sources(pico_btstack_base INTERFACE
+        $<IF:$<BOOL:$<IF:$<STREQUAL:$<TARGET_PROPERTY:PICO_TARGET_STDIO_RTT>,>,${PICO_STDIO_RTT},$<TARGET_PROPERTY:PICO_TARGET_STDIO_RTT>>>,,${PICO_BTSTACK_PATH}/3rd-party/segger-rtt/SEGGER_RTT.c>
+    )
+
     target_include_directories(pico_btstack_base_headers SYSTEM INTERFACE
         ${PICO_BTSTACK_PATH}/
         ${PICO_BTSTACK_PATH}/3rd-party/md5

src/rp2_common/pico_stdio_rtt/SEGGER/RTT/SEGGER_RTT.c

@@ -78,6 +78,11 @@ Additional information:
 
 #include <string.h>                 // for memcpy
 
+#ifdef __GNUC__
+#pragma GCC diagnostic ignored "-Wcast-qual"
+#pragma GCC diagnostic ignored "-Wcast-align"
+#endif
+
 /*********************************************************************
 *
 *       Configuration, default values

src/rp2_common/pico_stdio_rtt/stdio_rtt.c

@@ -26,11 +26,11 @@ void stdio_rtt_deinit(void) {
 }
 
 static void stdio_rtt_out_chars(const char *buf, int length) {
-    SEGGER_RTT_Write(0, buf, length);
+    SEGGER_RTT_Write(0, buf, (unsigned)length);
 }
 
 static int stdio_rtt_in_chars(char *buf, int length) {
-    return SEGGER_RTT_Read(0, buf, length);
+    return (int)SEGGER_RTT_Read(0, buf, (unsigned)length);
 }
 
 stdio_driver_t stdio_rtt = {