win32: define WIN32_LEAN_AND_MEAN

This makes windows.h include less headers.
Otherwise boolean is typedef'ed and that clashes with libjson.

configure.ac

@@ -91,6 +91,9 @@ case $host in
    *-*-darwin* )
       AC_DEFINE([_DARWIN_C_SOURCE], [200112L], [Needed to get NSIG on Mac OS X])
       ;;
+   *-*-mingw* )
+      AC_DEFINE([WIN32_LEAN_AND_MEAN], 1, [Needed to avoid including unnecessary headers])
+      ;;
 esac
 
 # M4

src/pulsecore/dllmain.c

@@ -30,6 +30,7 @@
 #include <string.h>
 
 #include <windows.h>
+#include <winsock2.h>
 
 extern pa_win32_get_toplevel(HANDLE handle);