Use the bootstrap libphobos2.a when linking the initially built dmd.

Index: dmd-bootstrap/openbsd/bin64/dmd.conf
--- dmd-bootstrap/openbsd/bin64/dmd.conf.orig
+++ dmd-bootstrap/openbsd/bin64/dmd.conf
@@ -2,4 +2,4 @@
 DFLAGS=-I${TRUEPREFIX}/include/dmd/phobos -I${TRUEPREFIX}/include/dmd/druntime/import -L-L/usr/lib -L-L${TRUEPREFIX}/lib -L--export-dynamic -fPIC
 
 [Environment64]
-DFLAGS=-I${TRUEPREFIX}/include/dmd/phobos -I${TRUEPREFIX}/include/dmd/druntime/import -L-L/usr/lib -L-L${TRUEPREFIX}/lib -L--export-dynamic -fPIC
+DFLAGS=-I%@P%/../../../dmd/druntime/src -I%@P%/../../../phobos -L-L%@P%/../../../phobos/generated/openbsd/release/64 -L--export-dynamic -fPIC -L-L%@P%/../../../dmd-bootstrap/openbsd/lib64
