relax space-in-field-name checks only if new MHD_USE_PERMISSIVE_CHECKS flag is set

doc/libmicrohttpd.texi

@@ -12,7 +12,7 @@ This manual is for GNU libmicrohttpd
 (version @value{VERSION}, @value{UPDATED}), a library for embedding
 an HTTP(S) server into C applications.
 
-Copyright @copyright{} 2007--2016 Christian Grothoff
+Copyright @copyright{} 2007--2017 Christian Grothoff
 
 @quotation
 Permission is granted to copy, distribute and/or modify this document
@@ -496,7 +496,7 @@ that IPv4 addresses are returned by MHD in the IPv6-mapped format
 (the 'struct sockaddr_in6' format will be used for IPv4 and IPv6).
 
 @item MHD_USE_PEDANTIC_CHECKS
-Be pedantic about the protocol (as opposed to as tolerant as possible).
+Be pedantic about the protocol.
 Specifically, at the moment, this flag causes MHD to reject HTTP
 1.1 connections without a @code{Host} header.  This is required by the
 standard, but of course in violation of the ``be as liberal as possible
@@ -504,6 +504,13 @@ in what you accept'' norm.  It is recommended to turn this @strong{ON}
 if you are testing clients against MHD, and @strong{OFF} in
 production.
 
+@item MHD_USE_PERMISSIVE_CHECKS
+Be permissive about the protocol, allowing slight deviations that are
+technically not allowed by the RFC.  Specifically, at the moment, this
+flag causes MHD to allow spaces in header field names.  This is
+disallowed by the standard.
+
+
 @item MHD_USE_POLL
 @cindex FD_SETSIZE
 @cindex poll