fix macro conflict

[kirazero17]

Somehow I've got this error while building ns-3.39 with p4sim:

/home/p4/ns-3/ns3.39/src/core/model/log.h:275:38: error: expected unqualified-id before numeric constant
  275 | #define NS_LOG_INFO(msg) NS_LOG(ns3::LOG_INFO, msg)

The enum LOG_INFO is conflicting with the behavioral model LOG_INFO and is replaced as ns3::<some number>, causing a compilation error.

[Mingyumaz]

I think PR #23 should remove all references to bmruntime.

bmruntime.pc may exist, but it points to -lbmruntime, while BMv2 does not actually install libbmruntime.so or libbmruntime.a into /usr/local/lib. The library is marked as non-installed by BMv2's autotools build system, so the linker fails with:

/usr/bin/ld: cannot find -lbmruntime

The correct dependency is already covered by bm.pc, which links against libbmall. libbmall contains the required bm_runtime symbols, so no separate bmruntime dependency is needed.

Suggested PR #23 changes:

• Remove bmruntime from third_party_libraries in CMakeLists.txt.
• Remove the find_library(BMRUNTIME_LIB ...) fallback search block.
• Remove the bmruntime.pc generation block from set_pkg_config_env.sh.

This avoids generating or using a broken pkg-config entry for a library that BMv2 does not install.