When OVS is built with --with-dpdk, every binary (ovs-ofctl, ovs-vsctl, ovsdb-server, etc.) gets linked with all DPDK libraries. Only ovs-vswitchd actually uses DPDK. This causes inflated binary sizes for static builds (~14-16 MB instead of ~2-3 MB) and unnecessary shared library dependencies for shared builds.

Fix implemented in:
https://github.com/drizzt/ovs/tree/isolate-dpdk-linking-main

A 3.6.0-friendly version, for backports, is also implemented in:
https://github.com/drizzt/ovs/tree/isolate-dpdk-linking

Changes:

• acinclude.m4: Save/restore LIBS around DPDK dependency detection to prevent DPDK libraries from polluting global LIBS.
• lib/automake.mk: Move DPDK sources into a separate libopenvswitchdpdk.la.
• lib/dpdk-stub.c: Always compile into libopenvswitch (not conditionally).
• lib/dpdk-link-stubs.c: New file with weak stubs for free_dpdk_buf and rte_get_tsc_hz, in a separate translation unit to avoid multiple definition conflicts when linking ovs-vswitchd.
• vswitchd/automake.mk: Link only ovs-vswitchd against libopenvswitchdpdk.la and DPDK_LIBS.

Result (static DPDK, stripped sizes):

• ovs-vswitchd: ~25 MB (unchanged, has full DPDK)
• ovs-ofctl, ovsdb-server, etc.: ~2-3 MB (down from ~14-16 MB)