ci/msys2: create a wrap file for libplacebo

This is required because msys2's libplacebo is too outdated

ci/build-msys2.sh

@@ -1,8 +1,19 @@
 #!/bin/sh -e
 
+mkdir subprojects
+cat > subprojects/libplacebo.wrap <<EOF
+[wrap-git]
+url = https://code.videolan.org/videolan/libplacebo.git
+revision = v6.338.1
+depth = 1
+clone-recursive = true
+EOF
+
 meson setup build            \
   --werror                   \
   -Dlibplacebo:werror=false  \
+  -Dlibplacebo:demos=false   \
+  -Dlibplacebo:default_library=static \
   -Dc_args="-Wno-error=deprecated -Wno-error=deprecated-declarations" \
   -D cdda=enabled            \
   -D d3d-hwaccel=enabled     \