Fix build against esp32-p4

- Bump esp-backtrace for esp32-p4 support, which removes the uart feature and delegates to esp-println
- Added esp-println dependency
- Add mapping for ESP32P4 and other risc-v esp-idf targets to the corresponding rust target triplet.
  Unfortunately there's no generic pattern like for xtensa, as can be seen on
  https://github.com/esp-rs/esp-idf-sys?tab=readme-ov-file#examples

api/cpp/CMakeLists.txt

@@ -159,6 +159,7 @@ if (SLINT_BUILD_RUNTIME)
     if (SLINT_FEATURE_FREESTANDING)
         if (ESP_PLATFORM)
             list(APPEND features "esp-backtrace/${IDF_TARGET}")
+            list(APPEND features "esp-println/${IDF_TARGET}")
         endif()
     else (SLINT_FEATURE_FREESTANDING)
         list(APPEND features std)

api/cpp/Cargo.toml

@@ -57,7 +57,8 @@ raw-window-handle = { version = "0.5", optional = true }
 # Enable image-rs' default features to make all image formats to C++ users
 image = { version = "0.24.0", optional = true }
 
-esp-backtrace = { version = "0.9.0", features = ["panic-handler", "print-uart"], optional = true }
+esp-backtrace = { version = "0.11.0", features = ["panic-handler", "println"], optional = true }
+esp-println = { version = "0.9.0", default-features = false, features = ["uart"], optional = true }
 
 [build-dependencies]
 anyhow = "1.0"

api/cpp/esp-idf/slint/CMakeLists.txt

@@ -9,9 +9,17 @@ idf_component_register(
 
 if (CONFIG_IDF_TARGET_ARCH_XTENSA)
     set(Rust_CARGO_TARGET "xtensa-${IDF_TARGET}-none-elf")
-else(CONFIG_IDF_TARGET_ARCH_XTENSA)
+elseif(CONFIG_IDF_TARGET_ARCH_RISCV)
+    if (CONFIG_IDF_TARGET_ESP32C6 OR CONFIG_IDF_TARGET_ESP32C5 OR CONFIG_IDF_TARGET_ESP32H2)
+        set(Rust_CARGO_TARGET "riscv32imac-esp-espidf")
+    elseif (CONFIG_IDF_TARGET_ESP32P4)
+        set(Rust_CARGO_TARGET "riscv32imafc-esp-espidf")
+    else ()
+        set(Rust_CARGO_TARGET "riscv32imc-esp-espidf")
+    endif()
+else()
     message(FATAL_ERROR "Architecture currently not supported")
-endif(CONFIG_IDF_TARGET_ARCH_XTENSA)
+endif()
 
 set(SLINT_FEATURE_FREESTANDING ON)
 set(SLINT_FEATURE_RENDERER_SOFTWARE ON)