Hi Girish,
Those architectures that are listed were known to work in specific points in time and are not guaranteed to remain so. Also, syslog-ng is an application written in C and is aimed to be portable to a number of architectures, which we also demonstrated in the amount of platforms that we support.
On this community mailing list, all we can do is help you if you have specific questions/issues. This may or may not match your level of expectations, but we can only guarantee that we put "best effort" in answering your questions and no guarantees.
Back to armv7, just like Peter Czanik has answered, we know about syslog-ng being used on this architecture, so it should theoretically be possible, but it's not something that the developers use every day, or which would be a primary platform (those being Linux distributions).
The toolchain and the environment matters, syslog-ng depends on a number of external libraries (glib for example, which you had an issue with in the past), and we generally assume that those are present on the system already.
That being said, Balabit does provide support for various platforms and as a commercial entity has the means and willingness to do testing in a wider variety of platforms and architectures. If you would like support guarantees, Balabit can most probably give that.