Fix build on GCC.
Fix build on GCC.

geofft/capnproto,MarPiRK/capnproto,jparyani/capnproto,jparyani/capnproto,nagyistoce/capnproto,mologie/capnproto,khklau/capnproto,martindale/capnproto,a-richardson/capnproto,modulexcite/capnproto,bsn069/capnproto,ligzy/capnproto,zarvox/capnproto,nagyistoce/capnproto,martindale/capnproto,mrdomino/capnproto,ligzy/capnproto,khklau/capnproto,MarPiRK/capnproto,rcrowder/capnproto,MarPiRK/capnproto,pjulien/capnproto,kamalmarhubi/capnproto,nagyistoce/capnproto,zarvox/capnproto,maurer/capnproto,Fraser999/capnproto,jparyani/capnproto,vladon/capnproto,bryce-gibson/capnproto,johnkdoe/capnproto,kamalmarhubi/capnproto,vladon/capnproto,a-richardson/capnproto,mologie/capnproto,kamalmarhubi/capnproto,joliss/capnproto,martindale/capnproto,pjulien/capnproto,a-richardson/capnproto,hntrmrrs/capnproto,zarvox/capnproto,ocdtrekkie/capnproto,johnkdoe/capnproto,Fraser999/capnproto,ligzy/capnproto,bsn069/capnproto,maurer/capnproto,Fraser999/capnproto,mrdomino/capnproto,maurer/capnproto,vladon/capnproto,modulexcite/capnproto,bryce-gibson/capnproto,bsn069/capnproto,joliss/capnproto,hntrmrrs/capnproto,bryce-gibson/capnproto,geofft/capnproto,rcrowder/capnproto,khklau/capnproto,ocdtrekkie/capnproto,joliss/capnproto,ocdtrekkie/capnproto,mologie/capnproto,rcrowder/capnproto,modulexcite/capnproto,geofft/capnproto,johnkdoe/capnproto,hntrmrrs/capnproto,pjulien/capnproto,mrdomino/capnproto