Dpkg::Shlibs::SymbolFile: assume an implicit version "Base" for unversioned symbols

debian/changelog

@@ -25,6 +25,8 @@ dpkg (1.15.3) UNRELEASED; urgency=low
     See dpkg-gensymbols(1) for more information. Closes: #521551
   * Do not include #MISSING lines in symbols files integrated in binary
     packages. Closes: #526251
+  * Assume an implicit version of "Base" for all unversioned symbols
+    that are merged into a SymbolFile. Closes: #533181
 
   [ Updated dpkg translations ]
   * Simplified Chinese (Deng Xiyue). Closes: #531387

scripts/Dpkg/Shlibs/SymbolFile.pm

@@ -266,7 +266,7 @@ sub merge_symbols {
 	if ($sym->{version}) {
 	    $dynsyms{$sym->{name} . '@' . $sym->{version}} = $sym;
 	} else {
-	    $dynsyms{$sym->{name}} = $sym;
+	    $dynsyms{$sym->{name} . '@Base' } = $sym;
 	}
     }