sd-boot: Add .osrel section

This allows starting systemd-boot from \EFI\Linux for easier testing
and bisection without risking an unbootable system as the user does not
need to replace their working loader.

src/boot/efi/boot.c

@@ -31,6 +31,12 @@
 /* magic string to find in the binary image */
 _used_ _section_(".sdmagic") static const char magic[] = "#### LoaderInfo: systemd-boot " GIT_VERSION " ####";
 
+/* Makes systemd-boot available from \EFI\Linux\ for testing purposes. */
+_used_ _section_(".osrel") static const char osrel[] =
+        "ID=systemd-boot\n"
+        "VERSION=\"" GIT_VERSION "\"\n"
+        "NAME=\"systemd-boot " GIT_VERSION "\"\n";
+
 enum loader_type {
         LOADER_UNDEFINED,
         LOADER_EFI,

src/boot/efi/meson.build

@@ -323,14 +323,15 @@ if have_gnu_efi
                         input : so,
                         output : tuple[1],
                         command : [objcopy,
-                                   '-j', '.text',
-                                   '-j', '.sdata',
-                                   '-j', '.sbat',
-                                   '-j', '.sdmagic',
                                    '-j', '.data',
                                    '-j', '.dynamic',
                                    '-j', '.dynsym',
+                                   '-j', '.osrel',
                                    '-j', '.rel*',
+                                   '-j', '.sbat',
+                                   '-j', '.sdata',
+                                   '-j', '.sdmagic',
+                                   '-j', '.text',
                                    efi_format,
                                    '@INPUT@', '@OUTPUT@'],
                         install : true,