Implement a minimum linux version build mechanism

We were about to use it for scull.c when we found a way to fix its build
intsead.

common.py

@@ -39,7 +39,7 @@ common = sys.modules[__name__]
 # Fixed parameters that don't depend on CLI arguments.
 consts = {}
 consts['repo_short_id'] = 'lkmc'
-consts['linux_kernel_version'] = '5.9.2'
+consts['linux_kernel_version'] = '.'.join(map(lambda i: str(i), path_properties.linux_kernel_version_tuple))
 # https://stackoverflow.com/questions/20010199/how-to-determine-if-a-process-runs-inside-lxc-docker
 consts['in_docker'] = os.path.exists('/.dockerenv')
 consts['root_dir'] = os.path.dirname(os.path.abspath(__file__))

path_properties.py

@@ -5,6 +5,8 @@ import signal
 
 from shell_helpers import LF
 
+linux_kernel_version_tuple = (5,9,2)
+
 class PathProperties:
     default_c_std = 'c11'
     default_cxx_std = 'c++17'
@@ -59,6 +61,7 @@ class PathProperties:
         'qemu_x86_64_int_syscall': False,
         'interactive': False,
         'minimum_gcc_version': (0, 0, 0),
+        'minimum_linux_version': (0, 0, 0),
         # The script takes a perceptible amount of time to run. Possibly an infinite loop.
         'more_than_1s': False,
         # The path should not be built. E.g.:
@@ -238,6 +241,8 @@ class PathProperties:
                 )
             ) and not (
                 self['minimum_gcc_version'] > self.current_gcc_version
+            ) and not (
+                self['minimum_linux_version'] > linux_kernel_version_tuple
             )
         )