Resolve a few issues with MSYS2 cross-builds

- Fix launching of subprocesses (missing gspawn helpers).
 - Discard unused GSettings schemas.
 - Make the program find its user guide.
 - Bundle a somewhat suboptimal version of ExifTool.

README.adoc

@@ -63,7 +63,7 @@ dependencies listed at the beginning of 'msys2-cross-configure.sh',
 plus rsvg-convert from librsvg2, and icotool from icoutils.
 Beware that the build will take up close to a gigabyte of disk space.
 
- $ sh msys2-cross-configure.sh builddir
+ $ sh -e msys2-cross-configure.sh builddir
  $ meson install -C builddir
 
 If everything succeeds, you will find a portable build of the application

fiv.c

@@ -1166,7 +1166,13 @@ static void
 show_help_contents(void)
 {
 	gchar *filename = g_strdup_printf("%s.html", PROJECT_NAME);
+#ifdef G_OS_WIN32
+	gchar *prefix = g_win32_get_package_installation_directory_of_module(NULL);
+	gchar *path = g_build_filename(prefix, PROJECT_DOCDIR, filename, NULL);
+	g_free(prefix);
+#else
 	gchar *path = g_build_filename(PROJECT_DOCDIR, filename, NULL);
+#endif
 	g_free(filename);
 	GError *error = NULL;
 	gchar *uri = g_filename_to_uri(path, NULL, &error);
@@ -1945,7 +1951,7 @@ output_thumbnail(gchar **uris, gboolean extract, const char *size_arg)
 
 #ifdef G_OS_WIN32
 	_setmode(fileno(stdout), _O_BINARY);
-#endif  // G_OS_WIN32
+#endif
 
 	GError *error = NULL;
 	GFile *file = g_file_new_for_uri(uris[0]);

meson.build

@@ -77,6 +77,10 @@ conf.set_quoted('PROJECT_NAME', meson.project_name())
 conf.set_quoted('PROJECT_VERSION', meson.project_version())
 conf.set_quoted('PROJECT_NS', application_ns)
 conf.set_quoted('PROJECT_DOCDIR', get_option('prefix') / docdir)
+if host_machine.system() == 'windows'
+	conf.set_quoted('PROJECT_DOCDIR', docdir)
+endif
+
 conf.set('HAVE_JPEG_QS', libjpegqs.found())
 conf.set('HAVE_LCMS2', lcms2.found())
 conf.set('HAVE_LIBRAW', libraw.found())
@@ -86,6 +90,7 @@ conf.set('HAVE_XCURSOR', xcursor.found())
 conf.set('HAVE_LIBHEIF', libheif.found())
 conf.set('HAVE_LIBTIFF', libtiff.found())
 conf.set('HAVE_GDKPIXBUF', gdkpixbuf.found())
+
 configure_file(
 	output : 'config.h',
 	configuration : conf,

msys2-cross-configure.sh

@@ -33,6 +33,11 @@ fetch() {
 		status Fetching "$name"
 		[ -f "packages/$name" ] || curl -#o "packages/$name" "$repository/$name"
 	done
+
+	name=exiftool-$(curl -# https://exiftool.org/ver.txt).zip
+	status Fetching "$name"
+	[ -f "$name" ] || curl -#o "$name" "https://exiftool.org/$name"
+	ln -sf "$name" exiftool.zip
 }
 
 verify() {
@@ -48,6 +53,8 @@ extract() {
 	for i in packages/*
 	do bsdtar -xf "$i" --strip-components 1 mingw64
 	done
+
+	bsdtar -xOf exiftool.zip > bin/exiftool.exe
 }
 
 configure() {

msys2-cross-install.sh

@@ -3,14 +3,17 @@ export LC_ALL=C
 cd "$MESON_INSTALL_DESTDIR_PREFIX"
 msys2_root=$1
 
-# Copy libraries we depend on, and a few files required by GTK+.
+# Copy libraries we depend on, and a few files required by GLib/GTK+.
+cp -p "$msys2_root"/bin/exiftool.exe .
 cp -p "$msys2_root"/bin/*.dll .
+# The console helper is only useful for debug builds.
+cp -p "$msys2_root"/bin/gspawn-*-helper*.exe .
 cp -pR "$msys2_root"/etc/ .
 
 mkdir -p lib
 cp -pR "$msys2_root"/lib/gdk-pixbuf-2.0/ lib
-mkdir -p share/glib-2.0
-cp -pR "$msys2_root"/share/glib-2.0/schemas/ share/glib-2.0
+mkdir -p share/glib-2.0/schemas
+cp -pR "$msys2_root"/share/glib-2.0/schemas/*.Settings.* share/glib-2.0/schemas
 mkdir -p share
 cp -pR "$msys2_root"/share/mime/ share
 mkdir -p share/icons