Fix LDFLAGS and work around a Fedora bug that broke pthread linking
Fix LDFLAGS and work around a Fedora bug that broke pthread linking

The Fedora bug caused the DT_NEEDED for libpthread to be omitted, and
the missing -Wl before no-undefined prevented binutils from detecting it.

-export-dynamic is unnecessary for libraries, so this removes it, too.

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