Fix search form generation to not modify $cgi->param(...)'s.
In git_header_html() we used to use $cgi->hidden(-name => "a") etc. to generate hidden fields; unfortunately to use this form it is required to modify $cgi->param("a") etc., which makes href(-replay,...) use wrong replay values. This for example made the "next" link on the bottom of the page has a=search instead of a=$action, and thus fails to get you to the next page.
Because in CGI the value of a hidden field is "sticky", there is no way to modify it short of modifying $cgi->param(...). Therefore it got replaced by generating <input type="hidden" ...> element [semi] directly.
Alternate solution would be for href(-replay,...) to use values saved in global variables, such as $action etc., instead of (re)reading them from $cgi->param($symbol).