context: move poll/win32 specifics into a sub-struct

Signed-off-by: Alejandro Mery <amery@geeks.cl>
introduce context->event_ops and the info->event selector

Signed-off-by: Alejandro Mery <amery@geeks.cl>
libev: mutilate and prepare for context->event_ops usage

Signed-off-by: Alejandro Mery <amery@geeks.cl>
libev: rename to lib/event-libev.c

Signed-off-by: Alejandro Mery <amery@geeks.cl>
select context->event_ops based on info->event

Signed-off-by: Alejandro Mery <amery@geeks.cl>
move lws_plat_service() implementations to context->event_ops->service()

Signed-off-by: Alejandro Mery <amery@geeks.cl>
libev: add initial implementation of event_ops->service()

Signed-off-by: Alejandro Mery <amery@geeks.cl>
move register, unregister and watching direction change into event_ops

Signed-off-by: Alejandro Mery <amery@geeks.cl>
libev: change test-client and test-server to set info->event for -e

Signed-off-by: Alejandro Mery <amery@geeks.cl>
libev: also select libev if the LWS_SERVER_OPTION_LIBEV flag is set

Signed-off-by: Alejandro Mery <amery@geeks.cl>
libev: implement socket_register(), socket_unregister() and socket_change()

Signed-off-by: Alejandro Mery <amery@geeks.cl>
https://github.com/warmcat/libwebsockets/commit/6ff28248aadc12b971d13b212587e63b49a4653f#commitcomment-8861797

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test-server: fix to compile using mingw

Signed-off-by: Alejandro Mery <amery@geeks.cl>
mingw cmake and rebuild script [CI/DEV]

Signed-off-by: Alejandro Mery <amery@geeks.cl>
alloc: make _lws_realloc static

Signed-off-by: Alejandro Mery <amery@geeks.cl>
context: unify libwebsocket_create_context()'s return

Signed-off-by: Alejandro Mery <amery@geeks.cl>
Add libwebsocket_call_all_protocol() and libwebsocket_call_all() helpers

to call a function for each connection

Signed-off-by: Alejandro Mery <amery@geeks.cl>