Build UCX targeting the x86-64-v2 micro-arch, without AVX

Author: fwyzard

ucx.spec

@@ -28,9 +28,12 @@ Requires: xpmem
   --enable-mt \
   --with-pic \
   --with-gnu-ld \
-  --with-avx \
+%ifarch x86_64
+  --with-march=x86-64-v2 \
   --with-sse41 \
   --with-sse42 \
+  --without-avx \
+%endif
   --without-go \
   --without-java \
 %if 0%{!?without_cuda:1}