build,win: remove extraneous -lshell32 (#4213)

I suggested in #4182 to add the flag
to configure.ac as well but seems we already link to it.

I've removed the first one, not the second one, in case libuv is linked
with --as-needed.

configure.ac

@@ -74,7 +74,7 @@ AM_CONDITIONAL([OS400],    [AS_CASE([$host_os],[os400],         [true], [false])
 AM_CONDITIONAL([SUNOS],    [AS_CASE([$host_os],[solaris*],      [true], [false])])
 AM_CONDITIONAL([WINNT],    [AS_CASE([$host_os],[mingw*],        [true], [false])])
 AS_CASE([$host_os],[mingw*], [
-    LIBS="$LIBS -lws2_32 -lpsapi -liphlpapi -lshell32 -luserenv -luser32 -ldbghelp -lole32 -luuid -lshell32"
+    LIBS="$LIBS -lws2_32 -lpsapi -liphlpapi -luserenv -luser32 -ldbghelp -lole32 -luuid -lshell32"
 ])
 AS_CASE([$host_os], [solaris2.10], [
     CFLAGS="$CFLAGS -DSUNOS_NO_IFADDRS"