gdb.base/sym-file.exp, hide guts of the custom loader.

gdb.base/sym-file.exp, hide guts of the custom loader.

This test uses a simple custom elf loader, implemented in
gdb.base/sym-file-loader.h|c.  This loader doesn't have a dlclose-like
function today, but I'll need one.  But, I found that the guts of the
loader are exposed too much to the client, making the interface more
complicated than necessary.  It's simpler if the loader just exports a
few dlopen/dlsym -style functions.  That's what this patch does.

Tested on x86_86 Fedora 17, native and gdbserver.

gdb/testsuite/
2014-04-15  Pedro Alves  <palves@redhat.com>

	* gdb.base/sym-file-loader.h: Move inclusion of <inttypes.h>,
	<ansidecl.h>, <elf/common.h> and <elf/external.h> to
	sym-file-loader.c.
	(Elf_External_Phdr, Elf_External_Ehdr, Elf_External_Shdr)
	(Elf_External_Sym, Elf_Addr, GET, GETADDR, struct segment): Move
	to sym-file-loader.c.
	(struct library): Forward declare.
	(load_shlib, lookup_function): Change prototypes.
	(find_shstrtab, find_strtab, find_shdr, find_symtab)
	(translate_offset): Remove declarations.
	(get_text_addr): New declaration.
	* gdb.base/sym-file-loader.c: Move inclusion of <inttypes.h>,
	<ansidecl.h>, <elf/common.h> and <elf/external.h> here from
	sym-file-loader.h.
	(Elf_External_Phdr, Elf_External_Ehdr, Elf_External_Shdr)
	(Elf_External_Sym, Elf_Addr, GET, GETADDR, struct segment): Move
	here from sym-file-loader.h.
	(struct library): New structure.
	(load_shlib, lookup_function): Change prototypes and adjust to
	work with a struct library.
	(find_shstrtab, find_strtab, find_shdr, find_symtab)
	(translate_offset): Make static.
	(get_text_addr): New function.
	* gdb.base/sym-file-main.c (main): Adjust to new loader interface.