add clangd and fix some linted warnings

.clangd

+CompileFlags:
+  Add: [-I/usr/arm-none-eabi/include]

.gitignore

 *.wow
 .directory
 case/stl
+.cache

CMakeLists.txt

 # See <http://www.gnu.org/licenses/>.
 # ----------------------------------------------------------------------------
 
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.5)
 
 # build MCUFont encoder host tool and convert included example fonts
 execute_process(COMMAND make
 project(gadget C CXX)
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 # initialize the Raspberry Pi Pico SDK
 pico_sdk_init()

include/log.h

 
 #include <stdarg.h>
 #include <stdbool.h>
+#include <inttypes.h>
 #include "pico/stdlib.h"
 
 // for output that is stored in the debug log.
 // will be re-played from buffer when terminal connects
 #ifndef PICOWOTA
 #define debug(fmt, ...) debug_log(true, \
-        "%08lu %s:%d: " fmt "\r\n", \
+        "%08" PRIu32 " %s:%d: " fmt "\r\n", \
         to_ms_since_boot(get_absolute_time()), \
         __func__, __LINE__, \
         ##__VA_ARGS__)

src/cache.c

 
     // now actually write contents back to flash
     uint32_t addr = CACHE_FLASH_OFFSET + (cache[i].page * PAGE_SIZE);
-    debug("flushing entry %d page %d at 0x%08lX", i, cache[i].page, addr);
+    debug("flushing entry %d page %d at 0x%08" PRIX32, i, cache[i].page, addr);
 
     struct cache_write_data tmp = { .addr = addr, .buff = cache[i].buff };
     int r = flash_safe_execute(cache_write_flash, &tmp, FLASH_LOCK_TIMEOUT_MS);

src/crafty.c

     uint8_t buff[2];
     int32_t r = ble_read(uuid_base, buff, sizeof(buff));
     if (r != sizeof(buff)) {
-        debug("ble_read unexpected value %ld", r);
+        debug("ble_read unexpected value %" PRId32, r);
         return -1;
     }
 
     uint8_t buff[2];
     int32_t r = ble_read(uuid_base, buff, sizeof(buff));
     if (r != sizeof(buff)) {
-        debug("ble_read unexpected value %ld", r);
+        debug("ble_read unexpected value %" PRId32, r);
         return -1;
     }
 
 
     int8_t r = ble_write(uuid_base, uuid_base2, buff, sizeof(buff));
     if (r != 0) {
-        debug("ble_write unexpected value %d", r);
+        debug("ble_write unexpected value %" PRId8, r);
     }
     return r;
 }
     uint16_t d = 0;
     int8_t r = ble_write(uuid_base, uuid_base2, (uint8_t *)&d, sizeof(d));
     if (r != 0) {
-        debug("ble_write unexpected value %d", r);
+        debug("ble_write unexpected value %" PRId8, r);
     }
     return r;
 }
     uint8_t buff[2];
     int32_t r = ble_read(uuid_base, buff, sizeof(buff));
     if (r != sizeof(buff)) {
-        debug("ble_read unexpected value %ld", r);
+        debug("ble_read unexpected value %" PRId32, r);
         return -1;
     }