Protect against strange values of SIGRTMIN and SIGRTMAX,

and change alignment of numbers.

SignalsPanel.c

@@ -40,25 +40,16 @@ Panel* SignalsPanel_new() {
       }
    }
    #if (defined(SIGRTMIN) && defined(SIGRTMAX))
-   // Real-time signals.
-   // SIGRTMIN and SIGRTMAX expand to libc internal functions and we have to
-   // grab their numbers at runtime.
-   static char buf[15]; // 15 == sizeof("xx SIGRTMIN+nn")
-   int rtmax;
-   for (int sig = SIGRTMIN; sig <= (rtmax = SIGRTMAX); i++, sig++) {
-      // Every signal between SIGRTMIN and SIGRTMAX are denoted in "SIGRTMIN+n"
-      // notation. This matches glibc's strsignal(3) behavior.
-      // We deviate from behaviors of Bash, ksh and Solaris intentionally.
-      if (sig == rtmax) {
-         snprintf(buf, 15, "%2d SIGRTMAX", sig);
-      } else {
+   if (SIGRTMAX - SIGRTMIN <= 100) {
+      static char buf[15];
+      for (int sig = SIGRTMIN; sig <= SIGRTMAX; i++, sig++) {
          int n = sig - SIGRTMIN;
-         snprintf(buf, 15, "%2d SIGRTMIN%+d", sig, n);
+         snprintf(buf, 15, "%2d SIGRTMIN%-+3d", sig, n);
          if (n == 0) {
             buf[11] = '\0';
          }
+         Panel_set(this, i, (Object*) ListItem_new(buf, sig));
       }
-      Panel_set(this, i, (Object*) ListItem_new(buf, sig));
    }
    #endif
    Panel_setHeader(this, "Send signal:");