Fix third_party build on unix
Fix third_party build on unix

google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools,or-tools/or-tools,or-tools/or-tools,google/or-tools,google/or-tools,or-tools/or-tools,or-tools/or-tools,google/or-tools,google/or-tools