build: Divide mit-krb5-gssapi link flags between LDFLAGS and LIBS

build: Divide mit-krb5-gssapi link flags between LDFLAGS and LIBS

From the comments nearby about not having --libs-only-L, it looks as
though the intention was to apply a split like this to all dependency
libraries where possible, and the only reason it was not done for
Kerberos is that krb5-config doesn't have that feature and pkg-config
was originally not supported here. For example, zlib, libssh and librtmp
all have their flags from pkg-config split in this way.

Now that pkg-config is supported here, we can do the intended split.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Gbp-Pq: Name build-Divide-mit-krb5-gssapi-link-flags-between-LDFLAGS-a.patch