Ada: Reserved word "all" should not need to be spelled in lowercase.

Ada: Reserved word "all" should not need to be spelled in lowercase.

Consider the following code:

   type Ptr is access all Integer;
   IP : Ptr := new Integer'(123);

IP is the Ada exception of a pointer to an integer. To dereference
the pointer and get its value, the user uses the reserved word "all"
as follow:

    (gdb) p ip.all
    $1 = 123

Ada being a case-insensitive language, the casing should not matter.
Unfortunately, for the reserved word "all", things don't work. For
instance:

    (gdb) p ip.ALL
    Type integer is not a structure or union type

This patch fixes the problem.

gdb/ChangeLog:

	* ada-lex.l (find_dot_all): Use strncasecmp instead of strncmp.

gdb/testsuite/ChangeLog:

        * gdb.ada/dot_all: New testcase.