Sets whether install logging to $INSTDIR\\install.log will happen. $INSTDIR must have a value before you call this function or it will not work. Note that the \e{NSIS_CONFIG_LOG} build setting must be set (\c{scons NSIS_CONFIG_LOG=yes}) when building (it is not set by default) to support this. See \R{build}{Building NSIS} for more information about recompiling NSIS.