Remove build path from RECORD files (closes #969352)

Flit tries to write relative paths but fails for some files. By removing the build path from the file the path becomes meaningfull on the system where the package is installed and we get a reproducible package.

dhpython/build/plugin_flit.py

@@ -25,6 +25,7 @@ import os
 import os.path as osp
 from pathlib import Path
 import shutil
+import fileinput
 try:
     import toml
 except ModuleNotFoundError:
@@ -76,6 +77,11 @@ class DebianInstaller(Installer):
             log.info("Installing scripts to %s", dirs['scripts'])
 
         self.write_dist_info(dirs['purelib'])
+        # Remove build path from RECORD files
+        records = Path(dirs['purelib']).glob("*.dist-info/RECORD")
+        with fileinput.input(files=records, inplace=True) as record:
+            for line in record:
+                print(line.replace(destdir, ''), end='')
         log.info("Writing dist-info %s", dirs['purelib'])