uClibc compatibility (#5270)

* uclibc compatibility

Adds compatibility with uclibc, the officially supported toolchain of the luckfox pico

* Explicitly link stdc++fs for std::filesystem

Bringing this over from buildroot-meshtastic

arch/portduino/portduino.ini

@@ -32,6 +32,7 @@ build_flags =
   -Isrc/platform/portduino
   -DRADIOLIB_EEPROM_UNSUPPORTED
   -DPORTDUINO_LINUX_HARDWARE
+  -lstdc++fs
   -lbluetooth
   -lgpiod
   -lyaml-cpp

src/mesh/StreamAPI.h

@@ -3,6 +3,7 @@
 #include "PhoneAPI.h"
 #include "Stream.h"
 #include "concurrency/OSThread.h"
+#include <cstdarg>
 
 // A To/FromRadio packet + our 32 bit header
 #define MAX_STREAM_BUF_SIZE (MAX_TO_FROM_RADIO_SIZE + sizeof(uint32_t))

src/modules/PositionModule.cpp

@@ -16,10 +16,7 @@
 #include "meshtastic/atak.pb.h"
 #include "sleep.h"
 #include "target_specific.h"
-
-extern "C" {
 #include <Throttle.h>
-}
 
 PositionModule *positionModule;
 

variants/portduino/platformio.ini

@@ -2,7 +2,8 @@
 extends = portduino_base
 ; The pkg-config commands below optionally add link flags.
 ; the || : is just a "or run the null command" to avoid returning an error code
-build_flags = ${portduino_base.build_flags} -O0 -I variants/portduino -I /usr/include
+build_flags = ${portduino_base.build_flags} -O0 -I variants/portduino
+  -I /usr/include
   !pkg-config --libs libulfius --silence-errors || :
   !pkg-config --libs openssl --silence-errors || :
 board = cross_platform