Makefile: directly export RUSTC_BOOTSTRAP=1

Suggested-by: bjorn3 <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

Makefile

@@ -460,7 +460,6 @@ READELF		= $(CROSS_COMPILE)readelf
 STRIP		= $(CROSS_COMPILE)strip
 endif
 RUSTC		= rustc
-RUSTC_BOOTSTRAP = 1
 RUSTDOC		= rustdoc
 RUSTFMT		= rustfmt
 CLIPPY_DRIVER	= clippy-driver
@@ -550,8 +549,10 @@ ifdef RUST_LIB_SRC
 	export RUST_LIB_SRC
 endif
 
+export RUSTC_BOOTSTRAP := 1
+
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
-export RUSTC RUSTC_BOOTSTRAP RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO
+export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO
 export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD