Add generic support for search box in page header

This adds the ability to show a search box in any pageheader with correct href and
hidden form data, but does not enable the box on any pages.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

cgit.h

@@ -55,6 +55,7 @@ extern int cgit_query_has_sha1;
 extern char *cgit_querystring;
 extern char *cgit_query_repo;
 extern char *cgit_query_page;
+extern char *cgit_query_search;
 extern char *cgit_query_head;
 extern char *cgit_query_sha1;
 extern char *cgit_query_sha2;
@@ -75,6 +76,7 @@ extern void htmlf(const char *format,...);
 extern void html_txt(char *txt);
 extern void html_ntxt(int len, char *txt);
 extern void html_attr(char *txt);
+extern void html_hidden(char *name, char *value);
 extern void html_link_open(char *url, char *title, char *class);
 extern void html_link_close(void);
 extern void html_filemode(unsigned short mode);
@@ -98,7 +100,7 @@ extern void cgit_print_error(char *msg);
 extern void cgit_print_date(unsigned long secs);
 extern void cgit_print_docstart(char *title, struct cacheitem *item);
 extern void cgit_print_docend();
-extern void cgit_print_pageheader(char *title);
+extern void cgit_print_pageheader(char *title, int show_search);
 
 extern void cgit_print_repolist(struct cacheitem *item);
 extern void cgit_print_summary();