[Core] Fix RISC-V toolchain installation

The risc-v toolchain is only available on distributions based on Debian 11+
so we check for their availability before installing them.

platforms/chibios/platform.mk

@@ -346,8 +346,8 @@ ifeq ($(strip $(MCU)), risc-v)
         endif
     endif
 
-    # Default to compiling with picolibc for RISC-V targets if available,
-    # which is available by default on current (bullseye) debian based systems.
+    # Default to compiling with picolibc for RISC-V targets if available, which
+    # is available by default on distributions based on Debian 11+.
     ifeq ($(shell $(TOOLCHAIN)gcc --specs=picolibc.specs -E - 2>/dev/null >/dev/null </dev/null ; echo $$?),0)
         # Toolchain specific Compiler flags
         # Note that we still link with our own linker script

util/install/debian.sh

@@ -11,12 +11,18 @@ _qmk_install_prepare() {
 _qmk_install() {
     echo "Installing dependencies"
 
-    sudo apt-get -yq install \
+    sudo apt-get --quiet --yes install \
         build-essential clang-format diffutils gcc git unzip wget zip \
         python3-pip binutils-avr gcc-avr avr-libc binutils-arm-none-eabi \
         gcc-arm-none-eabi libnewlib-arm-none-eabi avrdude dfu-programmer \
-        dfu-util teensy-loader-cli libhidapi-hidraw0 libusb-dev \
-        picolibc-riscv64-unknown-elf gcc-riscv64-unknown-elf binutils-riscv64-unknown-elf
+        dfu-util teensy-loader-cli libhidapi-hidraw0 libusb-dev
 
-    python3 -m pip install --user -r $QMK_FIRMWARE_DIR/requirements.txt
+    # RISC-V toolchains with picolibc support are only available for distributions based on Debian 11+.
+    if sudo apt-get install --simulate --quiet --yes picolibc-riscv64-unknown-elf gcc-riscv64-unknown-elf binutils-riscv64-unknown-elf > /dev/null 2>&1; then
+        sudo apt-get --quiet --yes install picolibc-riscv64-unknown-elf \
+            gcc-riscv64-unknown-elf \
+            binutils-riscv64-unknown-elf
+    fi
+
+    python3 -m pip install --user -r "$QMK_FIRMWARE_DIR"/requirements.txt
 }