Try to be a little more descriptive about the effect of this flag,
rather than parroting what was said in the paragraph just above.

Mention this maximum header size for the header callback cases

shoot, Dan Fandrich already had this pointed out...

Added pop3 username and password example as well as an explanation of
how path part of the URL is used under pop3.

Additionally have corrected a couple of typos.

Multiple auths in the same WWW-Authenticate header

Fixed in commit 7d81e3f7193b8c

This return code has not been used since 7.20.0 so we can stop
mentioning it for current libcurl.

Reported by: Thomas L. Shinnick

Elaborate what max_fd == -1 means

Remove the reference to CURLM_CALL_MULTI_PERFORM as modern libcurl
versions don't ever return that.

This error could be caused by configure scripts being run with -Werror
-Wall, which would lead to libcurl being detected as unusable.

Don't even declare the struct members for disabled features

Introducing the CURLSHE_NOT_BUILT_IN return code for the share interface
when trying to set a sharing option that has been disabled (or not
enabled) in the library.

Previously there was wording that made people uncertain of the exact
rules.

Feedback by: Julien Royer and Georg Lippitsch
URL: http://curl.haxx.se/mail/lib-2011-09/0357.html

Slight rewording of the CURLOPT_URL SMTP sub-section.

Corrected the incorrect use of hyphens on the three uses of
"zero-terminated" with "zero terminated" to match the rest of the
document.

Corrected the use of an out of place hyphen in CURLOPT_NOPROXY section.

With locking, plus test, plus documentation

Allow (*curl_write_callback) write callbacks to return
CURL_WRITEFUNC_OUT_OF_MEMORY to properly indicate libcurl of OOM conditions
inside the callback itself.

If a socket is larger than FD_SETSIZE, avoid using FD_SET() on the
platforms where this is possible.

Bug: http://curl.haxx.se/bug/view.cgi?id=3413274
Reported by: Tim Starling

Probably the wrong place, but I dont know better.

Suffix rules cannot have any prerequisites of their own.

Added envvars to specify OpenSSL include, libpath and lib.
Added rule to create curlbuild.h from curlbuild.h.dist.

All paths to dependencies now quoted; synced examples makefile.