cpu/riscv_common: Enable Rust applications

This contains a workaround for
https://github.com/rust-lang/rust-bindgen/issues/1555 (withouot which
bindgen would fail, with little information helping remedy the cause)

cpu/riscv_common/Kconfig

@@ -12,7 +12,7 @@ config CPU_ARCH_RISCV
     select HAS_NEWLIB
     select HAS_PERIPH_CORETIMER
     select HAS_PICOLIBC if '$(RIOT_CI_BUILD)' != '1'
-    #select HAS_RUST_TARGET
+    select HAS_RUST_TARGET
     select HAS_SSP
 
     select MODULE_MALLOC_THREAD_SAFE if TEST_KCONFIG

cpu/riscv_common/Makefile.features

@@ -8,7 +8,7 @@ FEATURES_PROVIDED += cpp
 FEATURES_PROVIDED += libstdcpp
 FEATURES_PROVIDED += newlib
 FEATURES_PROVIDED += periph_coretimer
-#FEATURES_PROVIDED += rust_target
+FEATURES_PROVIDED += rust_target
 FEATURES_PROVIDED += ssp
 
 # RISC-V toolchain on CI does not work properly with picolibc yet

makefiles/cargo-targets.inc.mk

@@ -11,7 +11,9 @@ CARGO_COMPILE_COMMANDS_FLAGS = --clang
 $(CARGO_COMPILE_COMMANDS): $(BUILDDEPS)
 	$(Q)DIRS="$(DIRS)" APPLICATION_BLOBS="$(BLOBS)" \
 	  "$(MAKE)" -C $(APPDIR) -f $(RIOTMAKE)/application.inc.mk compile-commands
+	@# replacement addresses https://github.com/rust-lang/rust-bindgen/issues/1555
 	$(Q)$(RIOTTOOLS)/compile_commands/compile_commands.py $(CARGO_COMPILE_COMMANDS_FLAGS) $(BINDIR) \
+	  | sed 's/"riscv-none-embed"/"riscv32"/g' \
 	  | $(LAZYSPONGE) $@