Remove duplicate symbols and add test case

When the event symbols were added to the public API, not all
of them were removed from the private exports list. Solaris
gets unhappy when there are duplicated symbols. Extend the
symfile check to test for this scenario

src/check-symfile.pl

@@ -5,9 +5,11 @@ die "syntax: $0 SYMFILE ELFLIB(S)" unless int(@ARGV) >= 2;
 my $symfile = shift @ARGV;
 my @elflibs = @ARGV;
 
-my @wantsyms;
+my %wantsyms;
 my %gotsyms;
 
+my $ret = 0;
+
 open SYMFILE, $symfile or die "cannot read $symfile: $!";
 
 while (<SYMFILE>) {
@@ -21,7 +23,12 @@ while (<SYMFILE>) {
 
     die "malformed line $_" unless /^\s*(\S+);$/;
 
-    push @wantsyms, $1;
+    if (exists $wantsyms{$1}) {
+	print STDERR "Symbol $1 is listed twice\n";
+	$ret = 1;
+    } else {
+	$wantsyms{$1} = 1;
+    }
 }
 close SYMFILE;
 
@@ -37,8 +44,6 @@ foreach my $elflib (@elflibs) {
     close NM;
 }
 
-my $ret = 0;
-
 foreach my $sym (@wantsyms) {
     next if exists $gotsyms{$sym};
 

src/libvirt_private.syms

@@ -1178,8 +1178,6 @@ virDirCreate;
 virDoubleToStr;
 virEnumFromString;
 virEnumToString;
-virEventAddHandle;
-virEventRemoveHandle;
 virFileAbsPath;
 virFileAccessibleAs;
 virFileBuildPath;