cmake/tools: Fix panic_immediate_abort deprecation in Rust build

Replace deprecated -Zbuild-std-features=panic_immediate_abort with
-Cpanic=immediate-abort compiler flag via RUSTFLAGS.

The panic_immediate_abort feature has been stabilized as a real panic
strategy in recent Rust nightly versions. The old method of enabling
it via -Zbuild-std-features is no longer supported and triggers a
compile error in core/src/panicking.rs.

Changes:
* cmake/nuttx_add_rust.cmake: Use RUSTFLAGS with -Cpanic=immediate-abort
* tools/Rust.mk: Use RUSTFLAGS with -Cpanic=immediate-abort

Signed-off-by: Huang Qi <huangqi3@xiaomi.com>

cmake/nuttx_add_rust.cmake

@@ -128,10 +128,10 @@ function(nuttx_add_rust)
   # Determine build profile based on CONFIG_DEBUG_FULLOPT
   if(CONFIG_DEBUG_FULLOPT)
     set(RUST_PROFILE "release")
-    set(RUST_DEBUG_FLAGS "-Zbuild-std-features=panic_immediate_abort")
+    set(RUST_PANIC_FLAGS "-Zunstable-options -Cpanic=immediate-abort")
   else()
     set(RUST_PROFILE "debug")
-    set(RUST_DEBUG_FLAGS "")
+    set(RUST_PANIC_FLAGS "")
   endif()
 
   # Get the Rust target triple
@@ -152,9 +152,9 @@ function(nuttx_add_rust)
     COMMAND
       ${CMAKE_COMMAND} -E env
       NUTTX_INCLUDE_DIR=${PROJECT_SOURCE_DIR}/include:${CMAKE_BINARY_DIR}/include:${CMAKE_BINARY_DIR}/include/arch
-      cargo build --${RUST_PROFILE} -Zbuild-std=std,panic_abort
-      ${RUST_DEBUG_FLAGS} --manifest-path ${CRATE_PATH}/Cargo.toml --target
-      ${RUST_TARGET} --target-dir ${RUST_BUILD_DIR}
+      RUSTFLAGS=${RUST_PANIC_FLAGS} cargo build --${RUST_PROFILE}
+      -Zbuild-std=std,panic_abort --manifest-path ${CRATE_PATH}/Cargo.toml
+      --target ${RUST_TARGET} --target-dir ${RUST_BUILD_DIR}
     COMMENT "Building Rust crate ${CRATE_NAME}"
     VERBATIM)
 

tools/Rust.mk

@@ -90,8 +90,8 @@ endef
 ifeq ($(CONFIG_DEBUG_FULLOPT),y)
 define RUST_CARGO_BUILD
 	NUTTX_INCLUDE_DIR=$(TOPDIR)/include:$(TOPDIR)/include/arch \
+    RUSTFLAGS="-Zunstable-options -Cpanic=immediate-abort" \
     cargo build --release -Zbuild-std=std,panic_abort \
-    -Zbuild-std-features=panic_immediate_abort \
 		--manifest-path $(2)/$(1)/Cargo.toml \
 		--target $(call RUST_TARGET_TRIPLE)
 endef