gdb/doc/

gdb/doc/
	* gdb.texinfo (Index Section Format): Change the version to 5.
	Describe the different formula.

gdb/
	Case insensitive lookups implementation.
	* dwarf2read.c: Include ctype.h.
	(struct mapped_index): New field version.
	(mapped_index_string_hash): New parameter index_version.  New comment
	for it.  Call tolower appropriately.
	(find_slot_in_mapped_hash): New variable cmp, initialize it, use it.
	Choose the right index version for mapped_index_string_hash.
	(dwarf2_read_index): Support also the index version 5.  Initialize the
	new struct mapped_index field version.
	(hash_strtab_entry): Pass INT_MAX for the new parameter, explain why.
	(find_slot): Explain the version needs.  Pass INT_MAX for the new
	parameter.
	(write_psymtabs_to_index): Produce version 5.
	* minsyms.c (lookup_minimal_symbol): New variable cmp, initialize it,
	use it.  New comment for SYMBOL_MATCHES_SEARCH_NAME.
	* psymtab.c (lookup_partial_symbol): Find the
	SYMBOL_MATCHES_SEARCH_NAME start of the found block of matching
	entries.
	* symtab.c (lookup_symbol_in_language): Remove the case_sensitive_off
	NAME lowercasing.
	(search_symbols): Pass REG_ICASE to regcomp for case_sensitive_off.
	(completion_list_add_name): New variable ncmp, initialize it, use it.
	* symtab.h (SYMBOL_HASH_NEXT): Always call tolower.
	* utils.c (strcmp_iw): Support case_sensitive_off.
	(strcmp_iw_ordered): Sort in a way compatible with case_sensitive_off.
	New function comment part.  New variables saved_string1,
	saved_string2 and case_pass.  Add a proper second pass.

gdb/testsuite/
	* gdb.base/fortran-sym-case.c: New file.
	* gdb.base/fortran-sym-case.exp: New file.
	* gdb.dwarf2/dw2-case-insensitive-debug.S: New file.
	* gdb.dwarf2/dw2-case-insensitive.c: New file.
	* gdb.dwarf2/dw2-case-insensitive.exp: New file.