diff --git a/rustc.spec b/rustc.spec
index 3a2dee0..e9f276e 100644
--- a/rustc.spec
+++ b/rustc.spec
@@ -1,6 +1,6 @@
 %define stage1 1
 Name:          rustc
-Version:       1.47.0
+Version:       1.50.0
 Release:       1mamba
 Summary:       The Rust programming language, designed to be a safe, concurrent, practical language
 Group:         Applications/Development
@@ -24,7 +24,6 @@ Requires:      lib%{name} = %{?epoch:%epoch:}%{version}-%{release}
 %if "%{stage1}" != "1"
 BuildRequires: rustc
 %endif
-BuildRoot:     %{_tmppath}/%{name}-%{version}-root
 
 %description
 The Rust programming language, designed to be a safe, concurrent, practical language.
@@ -47,8 +46,6 @@ This package contains the documentation for %{name}.
 
 %prep
 %setup -q -n %{name}-%{version}-src
-#-D -T
-#:<< _EOF
 #%patch0 -p0
 
 cat <<EOF > config.toml
@@ -89,12 +86,11 @@ rpath = false
 EOF
 
 %build
-#:<< _EOF
-./x.py build
+./x.py build %{_smp_mflags}
 
 %install
 [ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
-DESTDIR=%{buildroot} ./x.py install
+DESTDIR=%{buildroot} ./x.py install %{_smp_mflags}
 
 chmod +x %{buildroot}%{_libdir}/lib*.so*
 
@@ -103,8 +99,12 @@ cd %{buildroot}%{_libdir}
 %ifarch %{ix86}
 ln -sf rustlib/i686-unknown-linux-gnu/lib/*.so .
 %else
+%ifarch arm
+ln -sf rustlib/arm-unknown-linux-gnueabi/lib/*.so .
+%else
 ln -sf rustlib/%{_arch}-unknown-linux-gnu/lib/*.so .
 %endif
+%endif
 cd -
 
 %find_lang %{name} || touch %{name}.lang
@@ -141,9 +141,10 @@ cd -
 
 %files -n lib%{name}
 %defattr(-,root,root)
-%{_libdir}/libLLVM-11-rust-%{version}-stable.so*
+#%{_libdir}/libLLVM-11-rust-%{version}-stable.so*
 %{_libdir}/rustlib/src/rust/Cargo.lock
 %{_libdir}/libchalk_derive-*.so
+%{_libdir}/libserde_derive-*.so
 %{_libdir}/librustc*.so
 %{_libdir}/libstd-*.so
 %{_libdir}/libtest-*.so
@@ -159,14 +160,24 @@ cd -
 %dir %{_libdir}/rustlib/src/rust
 %dir %{_libdir}/rustlib/src/rust/library
 %{_libdir}/rustlib/src/rust/library/*
+%dir %{_libdir}/rustlib/src/rust/src/llvm-project
+%dir %{_libdir}/rustlib/src/rust/src/llvm-project/libunwind
+%{_libdir}/rustlib/src/rust/src/llvm-project/libunwind/.clang-format
+%{_libdir}/rustlib/src/rust/src/llvm-project/libunwind/*
 %{_libdir}/rustlib/uninstall.sh
 %ifarch %{ix86}
 %dir %{_libdir}/rustlib/i686-unknown-linux-gnu
 %{_libdir}/rustlib/i686-unknown-linux-gnu/*
 %else
+%ifarch arm
+%dir %{_libdir}/rustlib/%{_arch}-unknown-linux-gnueabi
+%{_libdir}/rustlib/%{_arch}-unknown-linux-gnueabi/*
+%else
 %dir %{_libdir}/rustlib/%{_arch}-unknown-linux-gnu
 %{_libdir}/rustlib/%{_arch}-unknown-linux-gnu/*
 %endif
+%endif
+%{_prefix}/libexec/cargo-credential-1password
 
 %files apidocs
 %defattr(-,root,root)
@@ -182,6 +193,9 @@ cd -
 #%doc README.md
 
 %changelog
+* Sat Feb 27 2021 Automatic Build System <autodist@mambasoft.it> 1.50.0-1mamba
+- automatic version update by autodist
+
 * Tue Nov 10 2020 Silvan Calarco <silvan.calarco@mambasoft.it> 1.47.0-1mamba
 - update to 1.47.0