$ gdc main.d -o ddwm
/tmp/ccSrSGXM.o: In function `_Dmain':
main.d:(.text+0x7f): undefined reference to `_D3bcd4xlib4Xlib7_XEvent6__initZ'
main.d:(.text+0xa0): undefined reference to `XOpenDisplay'
main.d:(.text+0xae): undefined reference to `XDefaultRootWindow'
main.d:(.text+0xbd): undefined reference to `XStringToKeysym'
main.d:(.text+0xcc): undefined reference to `XKeysymToKeycode'
main.d:(.text+0x105): undefined reference to `XGrabKey'
main.d:(.text+0x157): undefined reference to `XGrabButton'
main.d:(.text+0x1a9): undefined reference to `XGrabButton'
main.d:(.text+0x1ca): undefined reference to `XNextEvent'
main.d:(.text+0x1fe): undefined reference to `XRaiseWindow'
main.d:(.text+0x274): undefined reference to `XGrabPointer'
main.d:(.text+0x298): undefined reference to `XGetWindowAttributes'
main.d:(.text+0x2ea): undefined reference to `XCheckTypedEvent'
main.d:(.text+0x467): undefined reference to `XMoveResizeWindow'
main.d:(.text+0x48e): undefined reference to `XUngrabPointer'
collect2: ld returned 1 exit status