Slightly raise the minimum CPU architecture for Linux wheels to "core2".

Author: scoder

Makefile

@@ -50,7 +50,7 @@ wheel_manylinux: wheel_manylinux64 wheel_manylinux32
 wheel_manylinux32 wheel_manylinux64: dist/lxml-$(LXMLVERSION).tar.gz
 	time docker run --rm -t \
 		-v $(shell pwd):/io \
-		-e CFLAGS="-O3 -g1 -mtune=generic -pipe -fPIC -flto" \
+		-e CFLAGS="-O3 -g1 -march=core2 -pipe -fPIC -flto" \
 		-e LDFLAGS="$(LDFLAGS) -flto" \
 		-e LIBXML2_VERSION="$(MANYLINUX_LIBXML2_VERSION)" \
 		-e LIBXSLT_VERSION="$(MANYLINUX_LIBXSLT_VERSION)" \