remove exit() from lib. fix #634 (#696)

* remove exit() from lib. fix #634
* remove the UFATAL loglevel completely.

include/stlink/logging.h

@@ -10,11 +10,10 @@ extern "C" {
 #endif
 
 enum ugly_loglevel {
-	UDEBUG = 90,
-	UINFO  = 50,
-	UWARN  = 30,
-	UERROR = 20,
-	UFATAL = 10
+    UDEBUG = 90,
+    UINFO  = 50,
+    UWARN  = 30,
+    UERROR = 20
 };
 
 int ugly_init(int maximum_threshold);
@@ -33,8 +32,6 @@ int ugly_log(int level, const char *tag, const char *format, ...);
 #define WLOG(...) WLOG_HELPER(__VA_ARGS__, "")
 #define ELOG_HELPER(format, ...)   ugly_log(UERROR, UGLY_LOG_FILE, format, __VA_ARGS__)
 #define ELOG(...) ELOG_HELPER(__VA_ARGS__, "")
-#define fatal_helper(format, ...)  ugly_log(UFATAL, UGLY_LOG_FILE, format, __VA_ARGS__)
-#define fatal(...) fatal_helper(__VA_ARGS__, "")
 
 #ifdef	__cplusplus
 }

src/logging.c

@@ -41,12 +41,6 @@ int ugly_log(int level, const char *tag, const char *format, ...) {
     case UERROR:
         fprintf(stderr, "ERROR %s: ", tag);
         break;
-    case UFATAL:
-        fprintf(stderr, "FATAL %s: ", tag);
-        vfprintf(stderr, format, args);
-        exit(EXIT_FAILURE);
-        // NEVER GETS HERE!!!
-        break;
     default:
         fprintf(stderr, "%d %s: ", level, tag);
         break;