Sorry, I forgot the title the first time around! I get the following message from dub when using "--build=release":
Linking... .dub/build/myprogram-release-linux.posix-x86_64-dmd_2067-C1A5273464ACE9961E3F3BA6AC04084B/abairtts.o:(.data._D65TypeInfo_xC3std5range10interfaces18__T10InputRangeTiZ10InputRange6__initZ+0x10): undefined reference to `_D64TypeInfo_C3std5range10interfaces18__T10InputRangeTiZ10InputRange6__initZ' collect2: error: ld returned 1 exit status --- errorlevel 1 DUB version 0.9.23, built on Apr 3 2015 dmd 2.067.0 Also, if I set the flags manually (dlfags[1]), they are ignored and dub build in debug mode. [1] now -boundscheck=off, instead of -noboundscheck