Added LFS3_F_REGBMAP and LFS3_F_COMPACTMETA

These are unlikely to make much progress, but that doesn't seem like a
great reason to disallow these flags in lfs3_format:

  LFS3_F_REGBMAP      0x00002000  Repopulate the gbmap
  LFS3_F_COMPACTMETA  0x00008000  Compact metadata logs

These are actually guaranteed to do _no_ work when formatting _without_
the gbmap, but with the gbmap it's less clear. Looking forward to the
planned ckfactory feature, these may be useful for cleaning up any rbyd
commits created as a part of building the initial gbmap.

---

Also tweaked the formatting for LFS3_F_* flags a bit, including making
all ifdefs explicit (mainly ifdef LFS3_RDONLY). Mixed ifdefs are a real
pain to read.

No code changes.

tests/test_mount.toml

@@ -107,6 +107,8 @@ defines.CKPROGS = [false, true]
 defines.CKFETCHES = [false, true]
 defines.CKMETAPARITY = [false, true]
 defines.CKDATACKSUMS = [false, true]
+defines.REGBMAP = [false, true]
+defines.COMPACTMETA = [false, true]
 defines.CKMETA = [false, true]
 defines.CKDATA = [false, true]
 defines.GBMAP = [false, true]
@@ -117,6 +119,7 @@ if = [
     'LFS3_IFDEF_CKFETCHES(true, !CKFETCHES)',
     'LFS3_IFDEF_CKMETAPARITY(true, !CKMETAPARITY)',
     'LFS3_IFDEF_CKDATACKSUMS(true, !CKDATACKSUMS)',
+    'LFS3_IFDEF_YES_GBMAP(true, !REGBMAP)',
     'LFS3_IFDEF_GBMAP(true, !GBMAP)',
 ]
 code = '''
@@ -133,6 +136,10 @@ code = '''
                 | ((CKDATACKSUMS)
                     ? LFS3_IFDEF_CKDATACKSUMS(LFS3_F_CKDATACKSUMS, -1)
                     : 0)
+                | ((REGBMAP)
+                    ? LFS3_IFDEF_GBMAP(LFS3_F_REGBMAP, -1)
+                    : 0)
+                | ((COMPACTMETA) ? LFS3_F_COMPACTMETA : 0)
                 | ((CKMETA) ? LFS3_F_CKMETA : 0)
                 | ((CKDATA) ? LFS3_F_CKDATA : 0)
                 | ((GBMAP) ? LFS3_IFDEF_GBMAP(LFS3_F_GBMAP, -1) : 0),