needed, and being able to define it if appropriate for further configure tests
as well as for the generated config file.

Introduced reentrant.m4 intended for our reentrant related autotools/m4 macros.

actually verify if the test is properly working

setting as the one actually used when finally building the library.

now cause the definition of RECVFROM_TYPE_ARG2_IS_VOID, RECVFROM_TYPE_ARG5_IS_VOID
or RECVFROM_TYPE_ARG6_IS_VOID, as appropriate.

function recvfrom as a result of the info additionally logged when running on a
Solaris system.

The compiler error showed that the prototype being used on Solaris was the one
declared in line 427 of "/usr/include/sys/socket.h" as:

function(int,
         pointer to void,
         unsigned int,
         int,
         pointer to struct sockaddr,
         pointer to void) returning int

to the data type pointed by its respective argument and not the pointer type.

finds out its return type and the types of its arguments. Added definitions
for non-configure systems config files, and introduced macro sreadfrom which
will be used on udp sockets as a recvfrom() wrapper.

some systems" (http://curl.haxx.se/bug/view.cgi?id=1999181). The problem was
that the configure script did not use the _POSIX_MONOTONIC_CLOCK feature test
macro when checking monotonic clock availability. This is now fixed and the
monotonic clock will not be used unless the feature test macro is defined
with a value greater than zero indicating always supported.

enough at detecting compilation errors or at least it has been properly
configured to do so. Configuration heavily depends on this capability, so
if this compiler sanity check fails the configuration process will now fail.

AC_FOO_IFELSE macros, otherwise temp files are not removed.

Identation adjustment.

When cross compiling WinCE with the arm-wince-cegcc-gcc C compiler
symbol __CEGCC__ is defined and the unix-like compatibility layer
is used. For our purposes this is not a native Windows build.

When cross compiling WinCE with the arm-wince-mingw32ce-gcc C compiler
symbol __MINGW32CE__ is defined and the unix-like compatibility layer
is not used. For our purposes this _is_ a native Windows build.

when build target is not a native Windows one

HAVE_WINSOCK2_H shall not be defined.
HAVE_WS2TCPIP_H shall not be defined.

when function clock_gettime() is available and the monotonic timer is
also available. Otherwise, in some cases, librt or libposix4 could be used
for linking even when finally not using the clock_gettime() function due
to lack of the monotonic clock.

icc warning level with libcurl's

are not icc 9.0 specific.

libtool to skip C++ and Fortran checks in patchset:
http://cool.haxx.se/cvs.cgi/curl/ares/configure.ac.diff?r1=1.60&r2=1.64

FD_ISSET, and FD_ZERO macros emits warnings #1469 and #593.
So for icc 9.0 we also ignore warnings #1469 and #593.
* 593 warns on "variable __d0 was set but never used"
* 1469 warns on "cc clobber ignored"

*) Update CURL_CC_DEBUG_OPTS from curl's script

defining HAVE_SIGNAL_H if the header is available.

Added a check in configure that tests if the sig_atomic_t type is
available, defining HAVE_SIG_ATOMIC_T if it is available. Providing
a suitable default in setup_once.h if not available.

Added a check in configure that tests if the sig_atomic_t type is
already defined as volatile, defining HAVE_SIG_ATOMIC_T_VOLATILE
if it is available and already defined as volatile.

Reintroduce checking for HAVE_MSG_NOSIGNAL in configure script, so that we don't depend on header inclusion order for a valid check.