Update git submodule
Update git submodule

This fixes build with mingw as well as lz4 support:

3aad79d LZ4: Do not include arpa/inet.h in Windows builds
9287e53 LZ4: Add support for 24bit pixman surfaces
d167e2e LZ4: Fix the row alignment when it is not on a 32bit boundary
f76fc28 LZ4: Decode the image format from the stream
83c0d64 LZ4: Adjust reading the top_down flag
6049db4 LZ4: Fix output buffer size
ac26fd7 Remove redundant #if defined(SW_CANVAS_CACHE) || defined(SW_CANVAS_IMAGE_CACHE)
062bf67 Remove unused 'invers' arg from canvas_get_*
619b995 common: fix build with mingw
862b9b1 build-sys: Move pixman check to m4 macro
137b1a5 build-sys: Move opengl check to m4 macro
f9e0a64 build-sys: Move opus check to m4 macro
dd57d05 build-sys: Move celt check to m4 macro
fb3fe22 build-sys: Move smartcard check to m4 macro
df74a17 build-sys: Move posix checks to a separate m4 macro
2f1ba3b build-sys: Add fallback for AS_VAR_APPEND
2195369 build-sys: Small cleanup of AM_CPPFLAGS
ed873a9 build-sys: Remove unused WITH_SMARTCARD conditional
2da14b6 build-sys: Remove unused win32 check
5bfa9ca build-sys: Remove unused X check
268d3e3 Remove unused header file

elmarco/spice-gtk,Fantu/spice-gtk,fgouget/spice-gtk,SPICE/spice-gtk,elmarco/spice-gtk,guodong/spice-gtk,Fantu/spice-gtk,elmarco/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,fgouget/spice-gtk,guodong/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,flexVDI/spice-gtk,SPICE/spice-gtk,guodong/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,SPICE/spice-gtk,Fantu/spice-gtk,fgouget/spice-gtk,freedesktop-unofficial-mirror/spice__spice-gtk,flexVDI/spice-gtk,Fantu/spice-gtk,guodong/spice-gtk,SPICE/spice-gtk,elmarco/spice-gtk