rust: avoid all GCC plugins, not just the randstruct one

We can keep support for some of the GCC plugins. However, it is simpler
and safer to just disable GCC plugin support since they may be going
away anyway [0]. Furthermore, if they are kept, new or future ones
could also break Rust support in subtle ways. And, in any case, Rust
support with GCC-built kernels is very experimental. So, at least for
the moment, let's focus on other things.

[0] https://lwn.net/Articles/851090/

Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

init/Kconfig

@@ -2058,7 +2058,7 @@ config RUST
 	depends on HAVE_RUST
 	depends on RUST_IS_AVAILABLE
 	depends on !MODVERSIONS
-	depends on !GCC_PLUGIN_RANDSTRUCT
+	depends on !GCC_PLUGINS
 	select CONSTRUCTORS
 	help
 	  Enables Rust support in the kernel.

rust/Makefile

@@ -245,8 +245,7 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
 	-fno-reorder-blocks -fno-allow-store-data-races -fasan-shadow-offset=% \
 	-fzero-call-used-regs=% -fno-stack-clash-protection \
 	-fno-inline-functions-called-once \
-	--param=% --param asan-% \
-	$(GCC_PLUGINS_CFLAGS)
+	--param=% --param asan-%
 
 # Derived from `scripts/Makefile.clang`.
 BINDGEN_TARGET_arm	:= arm-linux-gnueabi