you'll see warnings when dpkg-genchanges runs. looks like you want the architecture file to list the one architecture explicitly, not list "any".
dpkg-genchanges: warning: package gdc-10-alpha-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-arm-linux-gnueabi in control file but not in files list dpkg-genchanges: warning: package gdc-10-arm-linux-gnueabihf in control file but not in files list dpkg-genchanges: warning: package gdc-10-aarch64-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-i686-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-mipsel-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-mips64-linux-gnuabi64 in control file but not in files list dpkg-genchanges: warning: package gdc-10-mips64el-linux-gnuabi64 in control file but not in files list dpkg-genchanges: warning: package gdc-10-mips64-linux-gnuabin32 in control file but not in files list dpkg-genchanges: warning: package gdc-10-powerpc-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-powerpc64-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-powerpc64le-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-m68k-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-riscv64-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-sh4-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-sparc64-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-s390x-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-x86-64-linux-gnux32 in control file but not in files list dpkg-genchanges: warning: package gdc-10-mips64el-linux-gnuabin32 in control file but not in files list dpkg-genchanges: warning: package gdc-10-mipsisa32r6-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-mipsisa32r6el-linux-gnu in control file but not in files list dpkg-genchanges: warning: package gdc-10-mipsisa64r6-linux-gnuabi64 in control file but not in files list dpkg-genchanges: warning: package gdc-10-mipsisa64r6el-linux-gnuabi64 in control file but not in files list dpkg-genchanges: warning: package gdc-10-mipsisa64r6-linux-gnuabin32 in control file but not in files list dpkg-genchanges: warning: package gdc-10-mipsisa64r6el-linux-gnuabin32 in control file but not in files list
