diff --git a/rust.spec b/rust.spec
index d46d6e9..d0f9d40 100644
--- a/rust.spec
+++ b/rust.spec
@@ -86,18 +86,22 @@
 %endif
 # Use hardening ldflags.
 %global rustflags -Clink-arg=-Wl,-z,relro,-z,now
+# eliminate complain from RPMlint
+%global nocomplain CPPFLAGS="%{optflags}"
 # Cargo use system libs if not bootstrapping
 %if !%with rust_bootstrap
 %global cargo_git LIBGIT2_SYS_USE_PKG_CONFIG=1
 %global cargo_ssh LIBSSH2_SYS_USE_PKG_CONFIG=1
-%endif
-# eliminate complain from RPMlint
-%global nocomplain CPPFLAGS="%{optflags}"
-
 # Must be exported before running x.py in both build and install
 # If the environments between build and install and different,
 # everything will be rebuilt during installation!
 %global build_env_vars RUSTFLAGS="%{rustflags}" %{cargo_git} %{cargo_ssh} %{nocomplain}
+%else
+%global build_env_vars RUSTFLAGS="%{rustflags}" %{nocomplain}
+%endif
+
+# enable the --with-rust_bootstrap flag
+%bcond_with rust_bootstrap
 
 Name:           rust
 Version:        1.32.0
@@ -144,7 +148,7 @@ ExclusiveArch:  x86_64 %{arm} aarch64 ppc64 ppc64le s390x %{ix86}
 %ifarch %{ix86}
 ExclusiveArch:  i686
 %endif
-# Reall LLVM minimum version should be 7.x, but rust has a fallback mode
+# Real LLVM minimum version should be 7.x, but rust has a fallback mode
 %if !%with bundled_llvm
 BuildRequires:  llvm-devel >= 6.0
 %endif