Review krb5 patches

[cristian-vijelie]

Review the patches on patchwork:
https://patchwork.unikraft.org/bundle/cvijelie/kerberos/

Note: only the 3 support libraries should be reviewed at the moment

[laurbrb]

Makefile.uk

• it doesn't have the copyright header;
• the patches directory is missing from the base folder;
• I think that we should suppress the warnings generated when building lib5crypto, libkrb5support and liberr_com using these flags: -Wno-unused-parameter, -Wno-shadow, -Wno-parentheses, -Wno-implicit-fallthrough, -Wno-missing-field-initializers, -Wno-empty-body, -Wno-suggest-attribute=format.

README.md

• besides of the typo, I suggest to reformulate the following sentence as follows:

	5 - When adding the libraru in the dependencies list, lib-krb5, the libraries should be like this:
	5 + When adding the library, lib-krb5, to the dependencies list, the libraries should be in this order:

Config.uk

• typo:

	10 - 	select LIBNEWLIB
	10 + 	select LIBNEWLIBC

• lib-krb5 also depends on libdl, so we can set libdl too(select LIBPOSIX_LIBDL);
• I know that the state of this library is 'Work In Progress", but in this version LIBGSSAPI_KRB5 is only declared and never used.

Glue code

• you can remove include/byteswap.h, since now it is included in newlib/musl-imported/include/.