Fix SIGUSR2 on MSWin32 and division by zero #78 PR#79

Thanks to @xlat

Closes #78
Closes #79

bin/nytprofhtml

@@ -158,7 +158,8 @@ if (defined($opt_lib)) {
     lib->import($opt_lib);
 }
 
-$SIG{USR2} = \&Carp::cluck;
+$SIG{USR2} = \&Carp::cluck
+    if exists $SIG{USR2}; # some platforms don't have SIGUSR2 (Windows)
 
 my $reporter = new Devel::NYTProf::Reader($opt_file, {
     quiet => 0,
@@ -1022,10 +1023,10 @@ sub package_subinfo_map_to_tm_data {
         my $total_time = $si->profile->{attribute}{profiler_duration};
         my $incl_time = $si->incl_time;
         push @html, sprintf "Inclusive time: %s, %.2f%%",
-                fmt_time($incl_time), $incl_time/$total_time*100;
+                fmt_time($incl_time), $total_time ? $incl_time/$total_time*100 : 0;
         my $excl_time = $si->excl_time;
         push @html, sprintf "Exclusive time: %s, %.2f%%",
-                fmt_time($excl_time), $excl_time/$total_time*100
+                fmt_time($excl_time), $total_time ? $excl_time/$total_time*100 : 0
             if $excl_time ne $incl_time;
 
         if (my $mrd = $si->recur_max_depth) {

bin/nytprofpf

@@ -113,7 +113,8 @@ if (defined($opt_lib)) {
     lib->import($opt_lib);
 }
 
-eval { $SIG{USR2} = \&Carp::cluck }; # some platforms don't have SIGUSR2 (Windows)
+$SIG{USR2} = \&Carp::cluck
+    if exists $SIG{USR2}; # some platforms don't have SIGUSR2 (Windows)
 
 my $reporter = new Devel::NYTProf::Reader($opt_file, {
     quiet => 0,