[PATCH v2 07/19] rust: kbuild: support `skip_clippy` for `rustc_procmacro`

[Miguel Ojeda <ojeda@kernel.org>]

Certain vendored crates, like the upcoming `zerocopy-derive`, do not
need to be built with Clippy since we `--cap-lints=allow` them anyway.

Thus add support to skip Clippy for proc macro crates.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index 9b5a3f9dd934..7b1db0d5d423 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -547,10 +547,10 @@ $(obj)/libsyn.rlib: private rustc_target_flags = $(syn-flags)
 $(obj)/libsyn.rlib: $(src)/syn/lib.rs $(obj)/libquote.rlib FORCE
 	+$(call if_changed_dep,rustc_procmacrolibrary)
 
-quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
+quiet_cmd_rustc_procmacro = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) P $@
       cmd_rustc_procmacro = \
 	$(rustc_target_envs) \
-	$(RUSTC_OR_CLIPPY) $(rust_common_flags) $(rustc_target_flags) \
+	$(if $(skip_clippy),$(RUSTC),$(RUSTC_OR_CLIPPY)) $(rust_common_flags) $(rustc_target_flags) \
 		-Clinker-flavor=gcc -Clinker=$(HOSTCC) \
 		-Clink-args='$(call escsq,$(KBUILD_PROCMACROLDFLAGS))' \
 		--emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
-- 
2.54.0