This option, which resolves to -w when CONFIG_CYGWIN_WINTOOL is
configured, is now appended to INCDIR in tools/Config.mk.
See git commit # 5eae32577e5d5226e5d3027c169eeb369f83f77d in the main
wget is missing from some system (like macOS and Windows native),
it's better to use curl to simplify build environment.
Signed-off-by: Huang Qi <huangqi3@xiaomi.com>
