Building from git master requires DEBUG

[wltjr]

This might be known and intentional, but without setting DEBUG, the following errors occur during build. The missing variables are wrapped in #ifdef DEBUG

../src/x11/xf86Wacom.c:706:34: error: ‘pInfo’ undeclared (first use in this function); did you mean ‘AgpInfo’?
  706 |         int n = xf86WaitForInput(pInfo->fd, 0);
      |                                  ^~~~~
      |                                  AgpInfo
../src/x11/xf86Wacom.c:706:34: note: each undeclared identifier is reported only once for each function it appears in
../src/x11/xf86Wacom.c: In function ‘wcmDevSwitchMode’:
../src/x11/xf86Wacom.c:857:37: error: ‘priv’ undeclared (first use in this function)
  857 |         return wcmDevSwitchModeCall(priv, is_absolute) ? Success : XI_BadMode;
      |                                     ^~~~