Static analysis issues

[samhocevar]

A contribution I got by e-mail:

[src/common/fd.c:274]: (error) Common realloc mistake: 'fds' nulled but not freed upon failure  
[src/common/fd.c:295]: (error) Common realloc mistake: 'files' nulled but not freed upon failure  
[src/libzzuf/debug.c:85]: (error) va_list 'args' was opened but not closed by va_end().  
[src/libzzuf/debug.c:115]: (error) va_list 'args' was opened but not closed by va_end().  
[src/zzat.c:468]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure  
[src/zzat.c:470]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure  
[src/zzat.c:472]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure  
[src/zzat.c:474]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure  
[src/zzat.c:420]: (error) Memory leak: tmp  
[test/bug-memory.c:27]: (error) Memory leak: tmp  
[test/zzone.c:51]: (error) Memory leak: buf  
[test/zzone.c:51]: (error) Memory leak: tmp  
[src/zzuf.c:668] -> [src/zzuf.c:670]: (performance) Variable 'tmp' is reassigned a value before the old one has been used.  
[src/zzat.c:509]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure  
[src/zzuf.c:742]: (warning) sprintf format string requires 1 parameter but 2 are given.                                                                                    
[src/zzat.c:497]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure                                                                              
[src/zzat.c:489]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure
[src/zzat.c:505]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure    
[src/zzat.c:519]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure    
[src/zzat.c:521]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure
[src/zzat.c:515]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure
[src/zzat.c:481]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure
[src/zzat.c:477]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure
[src/zzat.c:501]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure
[src/zzat.c:485]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure
[src/zzat.c:493]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure                          
[src/zzat.c:525]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure                     
[src/zzat.c:527]: (error) Common realloc mistake: 'retbuf' nulled but not freed upon failure