curl: Port to Haiku again

Re-apply change from commit v2.8.0~1683 (add initial support for HAIKU
OS, 2008-09-15) on updated upstream curl.  However, leave out the part
that was reverted by commit v3.0.0-rc1~541^2~1 (Haiku: Remove outdated
preprocessor checks, 2013-10-05).

Utilities/cmcurl/CMakeLists.txt

@@ -215,6 +215,8 @@ if(BEOS)
   check_library_exists_concat("bnetapi" closesocket HAVE_LIBBNETAPI)
 endif(BEOS)
 
+check_library_exists_concat("network" recv HAVE_LIBNETWORK)
+
 if(NOT NOT_NEED_LIBNSL)
   check_library_exists_concat("nsl"    gethostbyname  HAVE_LIBNSL)
 endif(NOT NOT_NEED_LIBNSL)

Utilities/cmcurl/include/curl/curl.h

@@ -82,7 +82,7 @@
 #include <sys/time.h>
 #endif
 
-#ifdef __BEOS__
+#if defined __BEOS__ || defined __HAIKU__
 #include <support/SupportDefs.h>
 #endif