btrfs-progs: print optional features in btrfs version

There's a number of optionally built features, print the list on the 2nd
line of 'btrfs version'. The format is same as for e.g. systemd:

$ btrfs version
btrfs-progs v6.9.2
+EXPERIMENTAL -INJECT -STATIC +LZO +ZSTD +UDEV +FSVERITY +ZONED CRYPTO=builtin

Signed-off-by: David Sterba <dsterba@suse.com>

btrfs.c

@@ -221,7 +221,62 @@ static const char * const cmd_version_usage[] = {
 
 static int cmd_version(const struct cmd_struct *unused, int argc, char **argv)
 {
+	static const char *features[] = {
+#if EXPERIMENTAL
+		"+"
+#else
+		"-"
+#endif
+		"EXPERIMENTAL",
+#ifdef INJECT
+		"+"
+#else
+		"-"
+#endif
+		"INJECT",
+#ifdef STATIC_BUILD
+		"+"
+#else
+		"-"
+#endif
+		"STATIC",
+#if defined(COMPRESSION_LZO) && COMPRESSION_LZO == 1
+		"+"
+#else
+		"-"
+#endif
+		"LZO",
+#if defined(COMPRESSION_ZSTD) && COMPRESSION_ZSTD == 1
+		"+"
+#else
+		"-"
+#endif
+		"ZSTD",
+#if defined(HAVE_LIBUDEV) && HAVE_LIBUDEV == 1
+		"+"
+#else
+		"-"
+#endif
+		"UDEV",
+#if defined(HAVE_LINUX_FSVERITY_H) && HAVE_LINUX_FSVERITY_H == 1
+		"+"
+#else
+		"-"
+#endif
+		"FSVERITY",
+#if defined(BTRFS_ZONED) && BTRFS_ZONED == 1
+		"+"
+#else
+		"-"
+#endif
+		"ZONED",
+		"CRYPTO=" CRYPTOPROVIDER,
+	};
+
 	printf("%s\n", PACKAGE_STRING);
+	for (int i = 0; i < ARRAY_SIZE(features); i++)
+		printf("%s%s", (i == 0 ? "" : " "), features[i]);
+	putchar('\n');
 	return 0;
 }
 static DEFINE_SIMPLE_COMMAND(version, "version");