updated after discussions and thinking

Fix excessive escaping.

Fix CURL_CHECK_HEADERS_ONCE

Fix MinGW/MSYS support in CURL_CHECK_FUNC_RECV and CURL_CHECK_FUNC_SEND.

Undefine symbols before redefining them.

Undefine correct symbol.

Oops !

Prevent definition of HAVE_WINxxx_H symbols and avoid inclusion of Windows headers when compiled with Cygwin in POSIX emulation mode.

Cludge fix for djgpp 2.03 or older; it doesn't have snprintf() etc.
So avoid using x_was_used().

Add types and qualifiers for getnameifo(), send() and recv().
(Yang Tse forgot about djgpp)

Use a more descriptive var name.

Get qualifier of arg 2 for send() apart into SEND_QUAL_ARG2.

Platforms that don't have/run configure need default values in their config files for:

HAVE_GETNAMEINFO, GETNAMEINFO_QUAL_ARG1, GETNAMEINFO_TYPE_ARG1, GETNAMEINFO_TYPE_ARG2, GETNAMEINFO_TYPE

Platforms that don't have/run configure need default values in their config files for:

HAVE_GETNAMEINFO, GETNAMEINFO_QUAL_ARG1, GETNAMEINFO_TYPE_ARG1, GETNAMEINFO_TYPE_ARG2, GETNAMEINFO_TYPE_ARG46, GETNAMEINFO_TYPE_ARG7

HAVE_RECV, RECV_TYPE_ARG1, RECV_TYPE_ARG2, RECV_TYPE_ARG3, RECV_TYPE_ARG4, RECV_TYPE_RETV

HAVE_SEND, SEND_TYPE_ARG1, SEND_TYPE_ARG2, SEND_TYPE_ARG3, SEND_TYPE_ARG4, SEND_TYPE_RETV

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Find out return types and argument types for functions recv() and send() at configuration stage.

Toshiyuki Maezawa fixed a problem where you couldn't override the
Proxy-Connection: header when using a proxy and not doing CONNECT.

Test HAVE_GETNAMEINFO definition before using GETNAMEINFO_XXX definitions.

Fix compiler warning.

Use CURL_CHECK_FUNC_GETNAMEINFO results in CURL_CHECK_NI_WITHSCOPEID

Make CURL_CHECK_NI_WITHSCOPEID actually try to compile NI_WITHSCOPEID when cross-compiling.

Fix shell globbing in CURL_CHECK_FUNC_GETNAMEINFO

Fix shell globbing in CURL_CHECK_FUNC_GETNAMEINFO

Fix shell globbing in CURL_CHECK_FUNC_GETNAMEINFO

Get some debug info

Get some debug info

Avoid shell globbing