Remove lru_cache on get_version

Does not play well with forking.

src/ocrmypdf/exec/_support.py

@@ -25,6 +25,7 @@ import sys
 from collections.abc import Mapping
 from contextlib import suppress
 from distutils.version import LooseVersion
+from functools import lru_cache
 from subprocess import PIPE, STDOUT, CalledProcessError
 from subprocess import run as subprocess_run
 

src/ocrmypdf/exec/ghostscript.py

@@ -21,7 +21,6 @@ import logging
 import os
 import re
 import warnings
-from functools import lru_cache
 from io import BytesIO
 from os import fspath
 from pathlib import Path
@@ -57,7 +56,6 @@ if os.name == 'nt':
     GS = Path(GS).stem
 
 
-@lru_cache(maxsize=1)
 def version():
     return get_version(GS)
 

src/ocrmypdf/exec/jbig2enc.py

@@ -17,14 +17,12 @@
 
 """Interface to jbig2 executable"""
 
-from functools import lru_cache
 from subprocess import PIPE
 
 from ocrmypdf.exceptions import MissingDependencyError
 from ocrmypdf.exec import get_version, run
 
 
-@lru_cache(maxsize=1)
 def version():
     return get_version('jbig2', regex=r'jbig2enc (\d+(\.\d+)*).*')
 

src/ocrmypdf/exec/pngquant.py

@@ -17,7 +17,6 @@
 
 """Interface to pngquant executable"""
 
-from functools import lru_cache
 from subprocess import run
 from tempfile import NamedTemporaryFile
 
@@ -27,7 +26,6 @@ from ocrmypdf.exceptions import MissingDependencyError
 from ocrmypdf.exec import get_version
 
 
-@lru_cache(maxsize=1)
 def version():
     return get_version('pngquant', regex=r'(\d+(\.\d+)*).*')
 

src/ocrmypdf/exec/unpaper.py

@@ -23,7 +23,6 @@
 import logging
 import os
 import shlex
-from functools import lru_cache
 from pathlib import Path
 from subprocess import PIPE, STDOUT, CalledProcessError
 from tempfile import TemporaryDirectory
@@ -37,7 +36,6 @@ from ocrmypdf.exec import run as external_run
 log = logging.getLogger(__name__)
 
 
-@lru_cache(maxsize=1)
 def version():
     return get_version('unpaper')