Unfortunately, version 0.24 still doesn't show all the games (the list view also utilizes AJAX). Fortunately, I found a way to fix it. You can get HTML code encapsulated in JSON in separate pages. Addresses are as follows: https://www.gog.com/en/account/ajax?a=gamesListMore&s=title&q=&t=0&p=PAGE_NUMBER
where PAGE_NUMBER starts at 0 and ends when the "html" field is an empty string.
Thus, my little upgrade here: http://mgol.eu/pliki/gogdownloader-0.24-mgol.tgz
For JSON parsing I've used libjsoncpp, so this is the additional dependency. This solution has the additional advantage of not downloading unnecessary HTML code as these AJAX responses provide only the code related to the game list.
I've also modified Makefile, adding jsoncpp to linker and changing incorrect usage:
1) .PHONY is used to only indicate targets that are not real files which obviously doesn't apply to gogdownloader
2) One of the main purposes of Makefile is not to enforce recompiling until one of source files changes. Thus, 'clean' shouldn't be added to a gogdownloader dependency.
Now it compiles the executable only if one of gogdownloader.h or gogdownloader.cpp file changes.
I added the -mgol suffix only to indicate that this is not the official 0.24 version. I hope Sude incorporates these changes to his future versions. :)