Keysyms: Fix missing hpYdiaeresis

The handling of keysym name guards (e.g. `#ifndef XK_Ydiaeresis`) was
incomplete and led to a missing keysym.

Make `sripts/makeheader` more robust to C macros handling.

include/xkbcommon/xkbcommon-keysyms.h

@@ -3207,6 +3207,7 @@ performance, or use of this material.
 #define XKB_KEY_hpmute_asciitilde         0x100000ac
 #define XKB_KEY_hplira                    0x100000af
 #define XKB_KEY_hpguilder                 0x100000be
+#define XKB_KEY_hpYdiaeresis              0x100000ee
 #define XKB_KEY_hpIO                      0x100000ee  /* deprecated alias for hpYdiaeresis */
 #define XKB_KEY_hplongminus               0x100000f6
 #define XKB_KEY_hpblock                   0x100000fc

scripts/makeheader

@@ -19,6 +19,9 @@ keysym_entry_pattern = re.compile(
     re.VERBOSE,
 )
 
+# Match keysym guarded by #ifndef
+keysym_ifndef_pattern = re.compile(r"^#ifndef\s+(?P<prefix>\w*)XK_(?P<name>\w+)\s*$")
+
 # Match remaining XK_ references in the comments, e.g we will replace:
 #       XF86XK_CamelCaseKernelName	_EVDEVK(kernel value)
 #       #define XKB_KEY_SunCompose		0x0000FF20	/* Same as XK_Multi_key */
@@ -28,6 +31,10 @@ keysym_entry_pattern = re.compile(
 xorgproto_keysym_prefix_pattern = re.compile(r"\b(?P<prefix>\w*)XK_(?!KOREAN\b)")
 
 
+def make_keysym_name(m: re.Match[str]) -> str:
+    return m.group("prefix") + m.group("name")
+
+
 def make_keysym_entry(m: re.Match[str]) -> str:
     """
     Perform the substitutions
@@ -74,21 +81,50 @@ print(
 """
 )
 
+keysyms: set[str] = set()
 for path in HEADERS:
+    pending_guarded_keysym: str | None = None
     with path.open("rt", encoding="utf-8") as header:
         for line in header:
-            if "#ifdef" in line or "#ifndef" in line or "#endif" in line:
+            # Duplicate keysym name guard
+            if m := keysym_ifndef_pattern.match(line):
+                if pending_guarded_keysym:
+                    raise ValueError(f"Nested #ifndef {pending_guarded_keysym}")
+                pending_guarded_keysym = make_keysym_name(m)
                 continue
 
-            # Remove #define _OSF_Keysyms and such.
-            if "#define _" in line:
+            # Ignore C macro #ifdef/#ifndef
+            elif line.startswith("#ifdef") or line.startswith("#ifndef"):
+                if pending_guarded_keysym:
+                    raise ValueError(f"Nested C macro {pending_guarded_keysym}")
                 continue
 
-            # Handle a duplicate definition in HPkeysyms.h which kicks in if
-            # it's not already defined.
-            if "XK_Ydiaeresis" in line and "0x100000ee" in line:
+            # Ignore C macro #endif and check end of keysym name guard
+            elif line.startswith("#endif"):
+                if pending_guarded_keysym:
+                    pending_guarded_keysym = None
                 continue
 
+            # Remove #define _OSF_Keysyms and such.
+            elif line.startswith("#define _"):
+                continue
+
+            # Keysym entry: proceed various tests
+            if line.startswith("#") and (m := keysym_entry_pattern.match(line)):
+                name = make_keysym_name(m)
+                # Check expected guarded keysym, if relevant
+                if pending_guarded_keysym and name != pending_guarded_keysym:
+                    raise ValueError(f"{path}: Malformed keysym name guard: {line}")
+                # Check if name already defined
+                elif name in keysyms:
+                    if pending_guarded_keysym:
+                        # Ignore guarded keysym
+                        continue
+                    else:
+                        raise ValueError(f"{path}: Unguarded redefinition: {line}")
+                else:
+                    keysyms.add(name)
+
             # Perform _EVDEV and XK_ substitutions
             line = keysym_entry_pattern.sub(make_keysym_entry, line)
             line = xorgproto_keysym_prefix_pattern.sub(r"XKB_KEY_\1", line)