syncqt: Fix module header install target creation

Modified a regular expression in syncqt.pl so that the special case of
a class beginning with another class does not lead to the exclusion of
the first one. This affects the generation of the install target for
generated class headers of Qt modules. Now the expression verifies the
class names are not identical.

Fixes: QTBUG-71323
Change-Id: I210b4d4c3ed64cf189594b95b10aa0e8495a19d2
Reviewed-by: Jörg Bornemann <[email protected]>

bin/syncqt.pl

@@ -1092,7 +1092,7 @@ ($$)
 #                                   }
                                     my $class_header = "$class ";
                                     $pri_install_gfiles .= $class_header
-                                        unless ($shadow || $pri_install_gfiles =~ $class_header);
+                                        unless ($shadow || $pri_install_gfiles =~ m/\b$class_header/);
                                     $injection .= ":$class";
                                 }