* ldfile.h (struct search_dirs): Added sysrooted field.

* ldfile.h (struct search_dirs): Added sysrooted field.
* ldlang.h (struct lang_input_statement_struct): Likewise.
* ldfile.c (ldfile_add_library_path): Mark sysrooted paths.
(ldfile_open_file_search): Look for sysrooted filename starting
with / in ld_sysroot instead of in the current directory.  Clear
sysrooted flag if it's found in the current directory.  Set it
from the search directory's sysrooted flag where it is found
otherwise.
* ldlang.c (ldlang_sysrooted_script): New static variable.
(new_afile): Mark search_file_enums as sysrooted if
ldlang_sysrooted_script.
(load_symbols): Set ldlang_sysrooted_script according to the
script's sysrooted field while processing it.
* ld.texinfo: Document INPUT behavior in sysroot.