CMake: Fix introspection on Windows

The list of source files to pass to g-ir-scanner is becoming too
long for Windows, as Windows imposes a 8192-character limit for command
lines, so we need to first transform that list into a listings file, and
then use the --filelist option for g-ir-scanner to build the
introspection files.

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 62e7945..dca71ed 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -646,6 +646,11 @@
     endif ()
   endforeach ()
 
+  file(REMOVE ${CMAKE_CURRENT_BINARY_DIR}/src/hb_gir_list)
+  foreach (s ${introspected_sources})
+    file(APPEND ${CMAKE_CURRENT_BINARY_DIR}/src/hb_gir_list "${s}\n")
+  endforeach ()
+
   # Finally, build the introspection files...
   add_custom_command(
     TARGET harfbuzz-gobject
@@ -675,9 +680,9 @@
       --library=harfbuzz
       -L${hb_libpath}
       ${extra_libs}
-      ${introspected_sources}
+      --filelist ${CMAKE_CURRENT_BINARY_DIR}/src/hb_gir_list
       -o ${hb_libpath}/HarfBuzz-0.0.gir
-    DEPENDS harfbuzz-gobject harfbuzz
+    DEPENDS harfbuzz-gobject harfbuzz ${CMAKE_CURRENT_BINARY_DIR}/src/hb_gir_list
   )
 
   add_custom_command(