Fix compiling clang on i486

This is a first-thing-that-worked patch to fix compiler error:
> ninja: error: '/usr/lib64/libz.so', needed by 'bin/clang-tblgen',
> missing and no known rule to make it

Apparently it doesn't work on i486, likely due to cross compilation.

Author: direc85

rpm/clang.spec

@@ -153,7 +153,7 @@ pushd build
 %endif
 	-DCLANG_INCLUDE_TESTS:BOOL=OFF \
 	-DLLVM_MAIN_SRC_DIR=%{_datadir}/llvm/src \
-%if 0%{?__isa_bits} == 64
+%ifarch aarch64
 	-DLLVM_LIBDIR_SUFFIX=64 \
 %else
 	-DLLVM_LIBDIR_SUFFIX= \