HTTP resume fix

Daniel (24 October)

- Based on David Hull's fix in bug report 804599, we now check for solaris and

- David Hull filed bug report #829827. It identified a problem with -C - if

  the full file already was downloaded and thus the server responded with a

  416. libcurl would then wrongly use the Content-Length: header and expect

  that size to get transfer, causing a "hang" until the server closed the

  connection and then an error 18 ("still N bytes data left of the transfer").

  Now we don't return any error at all, but I think libcurl should perhaps

  return some kind of info since the requested range was out of the size of

  the document.

- Based on David Hull's fix in bug report #804599, we now check for solaris and

  gcc in configure and set the -mimpure-text link flag for linking the lib

  better.

This release includes the following bugfixes:

 o builds better on Solaris 8+

 o HTTP-resuming an already downloaded file works better

 o builds better on Solaris 8+ with gcc

 o --disable-eprt works now

 o improved CA cert verification

 o --anyauth could bug when the first response had no body contents