Documentation|qmake: Documented some deng_* build options

doomsday/config.pri

@@ -13,6 +13,7 @@
 # CONFIG options for Doomsday:
 # - deng_aptstable              Include the stable apt repository .list
 # - deng_aptunstable            Include the unstable apt repository .list
+# - deng_ccache                 (Unix|Mac) Use ccache when compiling
 # - deng_fluidsynth             Build the FluidSynth sound driver
 # - deng_fmod                   Build the FMOD Ex sound driver
 # - deng_nativesdk              (Mac) Use current OS's SDK for non-distrib use
@@ -26,6 +27,9 @@
 # - deng_notools                Do not build and deploy the tools
 # - deng_openal                 Build the OpenAL sound driver
 # - deng_qtautoselect           (Mac) Select OS X SDK based on Qt version
+# - deng_qtgui                  Use the QtGui module in dep_deng2.pri
+# - deng_qtopengl               Use the QtOpenGL module in dep_deng2.pri
+# - deng_qtwidgets              Use the QtWidgets module in dep_deng2.pri
 # - deng_nopackres              Do not package the Doomsday resources
 # - deng_rangecheck             Parameter range checking/value assertions
 # - deng_snowberry              (Unix) Include Snowberry in installation