1. Automake: it is a warning, not a fatal error. If it builds, it builds...
2. Please read the code carefully. In the example you have provided is it reads as false OR condition, which evaluates to condition. This is an if statement without an if. The same test for the opposite can be written as true && ! condition which evaluates to true if the condion is false, again without an if.
3. The package glib-2.0-32bit is apparently not installed on your system;
4. The package libgstreamer1.0-32bit is apparently not installed on your system;
5. Because of 4. the directory needed in 5. is not created and therefore missing.

Apart from Ubuntu/Mint, the 64-bit versions of other distributions are usually problematic as build environment (this is an understatement).

Regards,

Audioniek.