Drop redundant declarations

- `CRT_fatalError()` is declared twice in CRT.h
- `Process_pidFormat`, `Process_writeField()` and `Process_compare` are
  declared twice in Process.h
- `btime` is defined in LinuxProcess.c and also declared in
  LinuxProcess.h, so drop in LinuxProcessList.h

CRT.h

@@ -168,8 +168,6 @@ void CRT_init(int delay, int colorScheme, bool allowUnicode);
 
 void CRT_done(void);
 
-void CRT_fatalError(const char* note);
-
 int CRT_readKey(void);
 
 void CRT_disableDelay(void);