bpo-36876: Re-organize the c-analyzer tool code. (gh-16841)

This is partly a cleanup of the code. It also is preparation for getting the variables from the source (cross-platform) rather than from the symbols.

The change only touches the tool (and its tests).

Tools/c-analyzer/c_analyzer/parser/source.py

@@ -0,0 +1,34 @@
+from . import preprocessor
+
+
+def iter_clean_lines(lines):
+    incomment = False
+    for line in lines:
+        # Deal with comments.
+        if incomment:
+            _, sep, line = line.partition('*/')
+            if sep:
+                incomment = False
+            continue
+        line, _, _ = line.partition('//')
+        line, sep, remainder = line.partition('/*')
+        if sep:
+            _, sep, after = remainder.partition('*/')
+            if not sep:
+                incomment = True
+                continue
+            line += ' ' + after
+
+        # Ignore blank lines and leading/trailing whitespace.
+        line = line.strip()
+        if not line:
+            continue
+
+        yield line
+
+
+def iter_lines(filename, *,
+               preprocess=preprocessor.run,
+               ):
+    content = preprocess(filename)
+    return iter(content.splitlines())