As the code already checks for it we can just as well make it official!

When checking for connections that are bound to a particular device we
must make sure we don't compare with a NULL pointer.

As it is already included by curlbuild.h if it exists on the platform it
was included here superfluously anyway.

Reported by: Dagobert Michelsen
Bug: http://curl.haxx.se/bug/view.cgi?id=3294509

There are systems (like NetWare) without its own gai_strerror()
function.

Now use gai_strerror() to get proper error messages when getaddrinfo()
has failed. Detect the function in configure.

Code based on work and suggestions by Jeff Pohlmeyer and Guenter Knauf

Inspired by a patch from OB.Conseil. Added test case 708 to verify.

Improved library search by check_function_exists_concat() macro:
it does not revert the list of libraries any more.

Improved OpenSSL library search: first find zlib, then search for
openssl libraries that may depend on zlib.

For Unix: openssl libraries can now be detected in nonstandard
locations. Supply CMAKE_LIBRARY_PATH to CMake on command line.

Added installation capability (very basic one yet).

When connecting to a socks or similar proxy we do the proxy handshake at
once when we know the TCP connect is completed and we only consider the
"connection" complete after the proxy handshake. This fixes test 564
which is now no longer considered disabled.

Reported by: Dmitri Shubin
Bug: http://curl.haxx.se/mail/lib-2011-04/0127.html

Source files given with absolute paths do not have the
-D directory specifier prepended.

The make target checksrc now works in the root makefile and in both the
src and lib directories.

It is also run automatically on "all" if configure --enable-debug was
used.

Make everything adhere to the standards upheld by checksrc.pl and now
run checksrc from the makefile on debug builds.

Useful when a known file just doesn't comply and there's no intention to
make it do so.

"if(a)" is our style, not "if( a )"

Since it now supports multiple files this will be faster and will show
problems for more file than one at a time - more convenient.

It now scans multiple files and outputs an error+warning count summary
at the end in case at least one was detected.

-D can be used to specify in which dir the files are located

The script now scans for conditions that starts with a space for
if/while/for lines.

And make the build fail if a warning or error was detected

By the use of a the new lib/checksrc.pl script that checks that our
basic source style rules are followed.

For now provide prototypes instead of including the
non-standard normalisation.h which is only available in the
"Internationalized Domain Names Mitigation APIs" download.

asyn-ares.c and asyn-thread.c are two separate backends that implement
the same (internal) async resolver API for libcurl to use. Backend is
specified at build time.

The internal resolver API is defined in asyn.h for asynch resolvers.

Fixed indents, coding conventions and white space edits.

Modified the c-ares completion callback function to again NOT read the
conn data when the ares handle is being taken down as then it may have
been freed already.

Introducing an internal API for handling of different async resolver
backends.

For now we directly import the Idn* symbols with the linker;
an upcoming release of OWC will have these added to the import
lib normaliz.lib, and prototypes are added to winnnls.h.

Rewritten code from a patch brought by Matteo Rocco.

Found with codespell.

Found with codespell.