Index: misc/fix-decls.py
===================================================================
--- misc/fix-decls.py	(revision f7428b16e721f80978c178e5269b7e75d4003bd0)
+++ misc/fix-decls.py	(revision f7428b16e721f80978c178e5269b7e75d4003bd0)
@@ -0,0 +1,186 @@
+#!/usr/bin/env python3
+
+from sys import stdout
+from pycparser import c_ast, c_generator, parse_file
+
+cross_gcc = "/opt/cross-m68k/bin/m68k-none-elf-gcc"
+
+class Visitor(c_ast.NodeVisitor):
+    gen = c_generator.CGenerator()
+
+    def __init__(self):
+        self.path = None
+
+        self.calls = {}
+        self.knows = {}
+
+        self.declares = {}
+        self.in_header = {}
+
+        self.decl = {}
+
+        self.max_decl = {}
+        self.max_head = {}
+
+        self.fix_head = {}
+        self.fix_decl = {}
+
+    def visit_FuncCall(self, node):
+        if node.coord.file != self.path:
+            return
+
+        if type(node.name) is not c_ast.ID:
+            return
+
+        if self.path not in self.calls:
+            self.calls[self.path] = set()
+
+        self.calls[self.path].add(node.name.name)
+        self.generic_visit(node)
+
+    def visit_path(self, path, ast):
+        self.path = path
+        self.visit(ast)
+        self.path = None
+
+        for node in ast.ext:
+            if type(node) is not c_ast.FuncDef:
+                continue
+
+            node.decl.storage = []
+            decl = self.gen.visit(node.decl)
+
+            if node.decl.name in self.decl and \
+               self.decl[node.decl.name] != decl:
+                raise Exception("declaration mismatch: {} vs. {}". \
+                                format(self.decl[node.decl.name], decl))
+
+            self.decl[node.decl.name] = decl
+
+        for node in ast.ext:
+            if type(node) is c_ast.Decl and \
+               type(node.type) is c_ast.FuncDecl:
+                decl = node
+
+            elif type(node) is c_ast.FuncDef:
+                decl = node.decl
+
+            else:
+                continue
+
+            if path not in self.knows:
+                self.knows[path] = set()
+
+            self.knows[path].add(decl.name)
+
+            if decl.coord.file != path:
+                continue
+
+            if type(node) is c_ast.Decl:
+                if path not in self.max_decl:
+                    self.max_decl[path] = -1;
+
+                if decl.coord.line > self.max_decl[path]:
+                    self.max_decl[path] = decl.coord.line
+
+            if path not in self.declares:
+                self.declares[path] = set()
+
+            self.declares[path].add(decl.name)
+
+            if path[-2:] == ".h":
+                if decl.name in self.in_header:
+                    raise Exception("duplicate definition of {}".format(decl.name))
+
+                self.in_header[decl.name] = path
+
+    def fix(self):
+        for path, calls in sorted(self.calls.items()):
+            knows = self.knows[path]
+            needs = calls - knows
+
+            for need in sorted(needs):
+                if need in self.in_header:
+                    if path not in self.fix_head:
+                        self.fix_head[path] = set()
+
+                    self.fix_head[path].add(self.in_header[need])
+
+                else:
+                    if path not in self.fix_decl:
+                        self.fix_decl[path] = set()
+
+                    self.fix_decl[path].add(self.decl[need])
+
+            no = 1
+
+            with open(path, "r") as f:
+                for line in f:
+                    if len(line) >= 8 and line[:8] == "#include":
+                        self.max_head[path] = no
+
+                    no += 1
+
+        for path, _ in sorted(self.calls.items()):
+            if path not in self.fix_head and path not in self.fix_decl:
+                continue
+
+            max_head = self.max_head[path] if path in self.max_head else None
+            max_decl = self.max_decl[path] if path in self.max_decl else None
+
+            if max_head is None:
+                max_head = max_decl
+
+            if max_decl is None:
+                max_decl = max_head
+
+            no = 1
+            out = []
+            extern = "extern "
+
+            with open(path, "r") as f:
+                for line in f:
+                    out.append(line)
+
+                    if "extern\t" in line:
+                        extern = "extern\t"
+
+                    if no == max_head and path in self.fix_head:
+                        out.append("\n")
+
+                        for head in sorted(self.fix_head[path]):
+                            out.append("#include \"{}\"\n".format(head.split("/")[-1]))
+
+                    if no == max_decl and path in self.fix_decl:
+                        out.append("\n")
+
+                        for decl in sorted(self.fix_decl[path]):
+                            out.append(extern + decl + ";\n")
+
+                    no += 1
+
+            with open(path, "w") as f:
+                for line in out:
+                    f.write(line)
+
+vis = Visitor()
+
+with open("misc/c-files.txt", "r") as f:
+    for path in f:
+        path = path.rstrip()
+
+        if path == "ram/wdfield.c": # breaks pycparser
+            continue
+
+        stdout.write("parsing {}                    \r".format(path))
+        stdout.flush()
+
+        ast = parse_file(path, use_cpp = True, cpp_path = cross_gcc,
+                         cpp_args = ["-E", "-I", "include", "-include", "predef.h"])
+        # ast.show()
+
+        vis.visit_path(path, ast)
+
+    print("")
+
+vis.fix()