Set _WIN32_WINNT in static deps

Set -D_WIN32_WINNT for static deps; unbound, in particular, needs this
as the latest version appears to rely on something only provided in
non-ancient windows to build properly.

This required moving _winver into the toolchain file so that it is
available earlier in cmake code (StaticBuild is included long before
win32.cmake), but also this seems a more appropriate place for it.

cmake/StaticBuild.cmake

@@ -167,6 +167,11 @@ if(APPLE)
   set(deps_CXXFLAGS "${deps_CXXFLAGS} -mmacosx-version-min=${CMAKE_OSX_DEPLOYMENT_TARGET}")
 endif()
 
+if(_winver)
+  set(deps_CFLAGS "${deps_CFLAGS} -D_WIN32_WINNT=${_winver}")
+  set(deps_CXXFLAGS "${deps_CXXFLAGS} -D_WIN32_WINNT=${_winver}")
+endif()
+
 
 if("${CMAKE_GENERATOR}" STREQUAL "Unix Makefiles")
   set(_make $(MAKE))

cmake/win32.cmake

@@ -13,9 +13,6 @@ option(WITH_WINDOWS_32 "build 32 bit windows" OFF)
 # GNU ld sees fit to merge *all* the .ident sections in object files
 # to .r[o]data section one after the other!
 add_compile_options(-fno-ident -Wa,-mbig-obj)
-# the minimum windows version, set to 6 rn because supporting older windows is hell
-set(_winver 0x0600)
-add_definitions(-D_WIN32_WINNT=${_winver})
 
 if(EMBEDDED_CFG)
   link_libatomic()

contrib/cross/mingw_core.cmake

@@ -1,4 +1,8 @@
-set(CMAKE_SYSTEM_VERSION 5.0)
+set(CMAKE_SYSTEM_VERSION 6.0)
+
+# the minimum windows version, set to 6 rn because supporting older windows is hell
+set(_winver 0x0600)
+add_definitions(-D_WIN32_WINNT=${_winver})
 
 # target environment on the build host system
 # second one is for non-root installs