Add spellchecker scripts for Octave and run spellcheck of documentation interpreter/doccheck: New directory for spelling/grammar scripts. interpreter/doccheck/README: Instructions for using scripts. interpreter/doccheck/spellcheck: Script to spellcheck a Texinfo file. interpreter/doccheck/aspell.conf: GNU Aspell configuration file for Octave documentation. interpreter/doccheck/aspell-octave.en.pws: Private Aspell dictionary. interpreter/doccheck/add_to_aspell_dict: Script to add new Octave-specific words to private Aspell dictionary. interpreter/octave.texi: New @nospell macro which forces Aspell to ignore the word marked by the macro. interpreter/mk_doc_cache.m: Skip new @nospell macro when building doc_cache.

--- a/src/syscalls.cc
+++ b/src/syscalls.cc
@@ -447,7 +447,7 @@
 Create the file if it does not exist.\n\
 \n\
 @item O_NONBLOCK\n\
-Nonblocking mode.\n\
+Non-blocking mode.\n\
 \n\
 @item O_SYNC\n\
 Wait for writes to complete.\n\