Update to C++ 20

Author: h2zero

.github/workflows/build.yml

@@ -45,7 +45,7 @@ jobs:
           cli-version: latest
           platforms: |
             - name: "n-able-Arduino:arm-ble"
-              source-url: "https://h2zero.github.io/n-able-Arduino/package_n-able_boards_index.json"
+              source-url: "https://h2zero.github.io/n-able-Arduino/package_n-able_boards_test_index.json"
               version: latest
             - name: "n-able-Arduino:arm-ble"
               source-path: .
@@ -118,7 +118,7 @@ jobs:
         run: |
           cat > example/platformio.ini << EOF
             [env]
-            platform = https://github.com/h2zero/platform-n-able.git
+            platform = https://github.com/h2zero/platform-n-able.git#cpp20
             platform_packages = framework-n-able-arduino @ file://./framework
             framework = arduino
             ${{ matrix.flags }}

platform.txt

@@ -28,15 +28,15 @@ compiler.warning_flags.default=
 compiler.warning_flags.more=-Wall
 compiler.warning_flags.all=-Wall -Wextra
 
-compiler.path={runtime.tools.gcc-arm-none-eabi-9.3.1-1.path}/bin/
+compiler.path={runtime.tools.gcc-arm-none-eabi-10.3.1-2.1.path}/bin/
 compiler.c.cmd=arm-none-eabi-gcc
 compiler.c.flags=-mcpu={build.mcu} -mthumb -c -g -Os {compiler.warning_flags} {build.float_flags} -Wno-unused-parameter -Wno-sign-compare -Wno-old-style-declaration -std=gnu17 -ffunction-sections -fdata-sections -nostdlib --param max-inline-insns-single=500 -MMD
 compiler.c.elf.cmd=arm-none-eabi-g++
 compiler.c.elf.flags=-Os -Wl,--gc-sections -save-temps
 compiler.S.cmd=arm-none-eabi-gcc
 compiler.S.flags=-c -g -x assembler-with-cpp
 compiler.cpp.cmd=arm-none-eabi-g++
-compiler.cpp.flags=-mcpu={build.mcu} -mthumb -c -g -Os {compiler.warning_flags} {build.float_flags} -Wno-unused-parameter -std=gnu++17 -ffunction-sections -fdata-sections -fno-threadsafe-statics -nostdlib --param max-inline-insns-single=500 -fno-rtti -fno-exceptions -MMD
+compiler.cpp.flags=-mcpu={build.mcu} -mthumb -c -g -Os {compiler.warning_flags} {build.float_flags} -Wno-unused-parameter -std=gnu++20 -ffunction-sections -fdata-sections -fno-threadsafe-statics -nostdlib --param max-inline-insns-single=500 -fno-rtti -fno-exceptions -MMD
 compiler.ar.cmd=arm-none-eabi-ar
 compiler.ar.flags=rcs
 compiler.objcopy.cmd=arm-none-eabi-objcopy