Yesterday I ran "make dist" but compiling was more than 4 hours(I don't know, which time it could, if I didn't press stop). Today I run "make dist" again and compiling very long time again. Is it normal? I have Mac mini 2012, 10gb ram.
That's normal because by default make only runs one build task at a time. Try running "make -j8 dist", which tells make to run up to 8 tasks at a time.
The easiest way to install j2objc is to download and unzip its most recent distribution.