SCons: Format buildsystem files with psf/black

Configured for a max line length of 120 characters.

psf/black is very opinionated and purposely doesn't leave much room for
configuration. The output is mostly OK so that should be fine for us,
but some things worth noting:

- Manually wrapped strings will be reflowed, so by using a line length
  of 120 for the sake of preserving readability for our long command
  calls, it also means that some manually wrapped strings are back on
  the same line and should be manually merged again.

- Code generators using string concatenation extensively look awful,
  since black puts each operand on a single line. We need to refactor
  these generators to use more pythonic string formatting, for which
  many options are available (`%`, `format` or f-strings).

- CI checks and a pre-commit hook will be added to ensure that future
  buildsystem changes are well-formatted.

core/SCsub

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 
-Import('env')
+Import("env")
 
 import core_builders
 import make_binders
@@ -11,31 +11,32 @@ env.core_sources = []
 
 # Generate AES256 script encryption key
 import os
+
 txt = "0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0"
-if ("SCRIPT_AES256_ENCRYPTION_KEY" in os.environ):
+if "SCRIPT_AES256_ENCRYPTION_KEY" in os.environ:
     e = os.environ["SCRIPT_AES256_ENCRYPTION_KEY"]
     txt = ""
     ec_valid = True
-    if (len(e) != 64):
+    if len(e) != 64:
         ec_valid = False
     else:
 
         for i in range(len(e) >> 1):
-            if (i > 0):
+            if i > 0:
                 txt += ","
-            txts = "0x" + e[i * 2:i * 2 + 2]
+            txts = "0x" + e[i * 2 : i * 2 + 2]
             try:
                 int(txts, 16)
             except:
                 ec_valid = False
             txt += txts
-    if (not ec_valid):
+    if not ec_valid:
         txt = "0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0"
         print("Invalid AES256 encryption key, not 64 bits hex: " + e)
 
 # NOTE: It is safe to generate this file here, since this is still executed serially
 with open("script_encryption_key.gen.cpp", "w") as f:
-    f.write("#include \"core/project_settings.h\"\nuint8_t script_encryption_key[32]={" + txt + "};\n")
+    f.write('#include "core/project_settings.h"\nuint8_t script_encryption_key[32]={' + txt + "};\n")
 
 
 # Add required thirdparty code.
@@ -49,7 +50,6 @@ thirdparty_misc_sources = [
     # C sources
     "fastlz.c",
     "smaz.c",
-
     # C++ sources
     "hq2x.cpp",
     "pcg.cpp",
@@ -60,30 +60,30 @@ thirdparty_misc_sources = [thirdparty_misc_dir + file for file in thirdparty_mis
 env_thirdparty.add_source_files(env.core_sources, thirdparty_misc_sources)
 
 # Zlib library, can be unbundled
-if env['builtin_zlib']:
-	thirdparty_zlib_dir = "#thirdparty/zlib/"
-	thirdparty_zlib_sources = [
-		"adler32.c",
-		"compress.c",
-		"crc32.c",
-		"deflate.c",
-		"infback.c",
-		"inffast.c",
-		"inflate.c",
-		"inftrees.c",
-		"trees.c",
-		"uncompr.c",
-		"zutil.c",
-	]
-	thirdparty_zlib_sources = [thirdparty_zlib_dir + file for file in thirdparty_zlib_sources]
-
-	env_thirdparty.Prepend(CPPPATH=[thirdparty_zlib_dir])
-	# Needs to be available in main env too
-	env.Prepend(CPPPATH=[thirdparty_zlib_dir])
-	if (env['target'] == 'debug'):
-		env_thirdparty.Append(CPPDEFINES=['ZLIB_DEBUG'])
-
-	env_thirdparty.add_source_files(env.core_sources, thirdparty_zlib_sources)
+if env["builtin_zlib"]:
+    thirdparty_zlib_dir = "#thirdparty/zlib/"
+    thirdparty_zlib_sources = [
+        "adler32.c",
+        "compress.c",
+        "crc32.c",
+        "deflate.c",
+        "infback.c",
+        "inffast.c",
+        "inflate.c",
+        "inftrees.c",
+        "trees.c",
+        "uncompr.c",
+        "zutil.c",
+    ]
+    thirdparty_zlib_sources = [thirdparty_zlib_dir + file for file in thirdparty_zlib_sources]
+
+    env_thirdparty.Prepend(CPPPATH=[thirdparty_zlib_dir])
+    # Needs to be available in main env too
+    env.Prepend(CPPPATH=[thirdparty_zlib_dir])
+    if env["target"] == "debug":
+        env_thirdparty.Append(CPPDEFINES=["ZLIB_DEBUG"])
+
+    env_thirdparty.add_source_files(env.core_sources, thirdparty_zlib_sources)
 
 # Minizip library, could be unbundled in theory
 # However, our version has some custom modifications, so it won't compile with the system one
@@ -99,7 +99,7 @@ env_thirdparty.add_source_files(env.core_sources, thirdparty_minizip_sources)
 # Zstd library, can be unbundled in theory
 # though we currently use some private symbols
 # https://github.com/godotengine/godot/issues/17374
-if env['builtin_zstd']:
+if env["builtin_zstd"]:
     thirdparty_zstd_dir = "#thirdparty/zstd/"
     thirdparty_zstd_sources = [
         "common/debug.c",
@@ -142,32 +142,45 @@ if env['builtin_zstd']:
 env.add_source_files(env.core_sources, "*.cpp")
 
 # Certificates
-env.Depends("#core/io/certs_compressed.gen.h", ["#thirdparty/certs/ca-certificates.crt", env.Value(env['builtin_certs']), env.Value(env['system_certs_path'])])
-env.CommandNoCache("#core/io/certs_compressed.gen.h", "#thirdparty/certs/ca-certificates.crt", run_in_subprocess(core_builders.make_certs_header))
+env.Depends(
+    "#core/io/certs_compressed.gen.h",
+    ["#thirdparty/certs/ca-certificates.crt", env.Value(env["builtin_certs"]), env.Value(env["system_certs_path"])],
+)
+env.CommandNoCache(
+    "#core/io/certs_compressed.gen.h",
+    "#thirdparty/certs/ca-certificates.crt",
+    run_in_subprocess(core_builders.make_certs_header),
+)
 
 # Make binders
-env.CommandNoCache(['method_bind.gen.inc', 'method_bind_ext.gen.inc', 'method_bind_free_func.gen.inc'], 'make_binders.py', run_in_subprocess(make_binders.run))
+env.CommandNoCache(
+    ["method_bind.gen.inc", "method_bind_ext.gen.inc", "method_bind_free_func.gen.inc"],
+    "make_binders.py",
+    run_in_subprocess(make_binders.run),
+)
 
 # Authors
-env.Depends('#core/authors.gen.h', "../AUTHORS.md")
-env.CommandNoCache('#core/authors.gen.h', "../AUTHORS.md", run_in_subprocess(core_builders.make_authors_header))
+env.Depends("#core/authors.gen.h", "../AUTHORS.md")
+env.CommandNoCache("#core/authors.gen.h", "../AUTHORS.md", run_in_subprocess(core_builders.make_authors_header))
 
 # Donors
-env.Depends('#core/donors.gen.h', "../DONORS.md")
-env.CommandNoCache('#core/donors.gen.h', "../DONORS.md", run_in_subprocess(core_builders.make_donors_header))
+env.Depends("#core/donors.gen.h", "../DONORS.md")
+env.CommandNoCache("#core/donors.gen.h", "../DONORS.md", run_in_subprocess(core_builders.make_donors_header))
 
 # License
-env.Depends('#core/license.gen.h', ["../COPYRIGHT.txt", "../LICENSE.txt"])
-env.CommandNoCache('#core/license.gen.h', ["../COPYRIGHT.txt", "../LICENSE.txt"], run_in_subprocess(core_builders.make_license_header))
+env.Depends("#core/license.gen.h", ["../COPYRIGHT.txt", "../LICENSE.txt"])
+env.CommandNoCache(
+    "#core/license.gen.h", ["../COPYRIGHT.txt", "../LICENSE.txt"], run_in_subprocess(core_builders.make_license_header)
+)
 
 # Chain load SCsubs
-SConscript('os/SCsub')
-SConscript('math/SCsub')
-SConscript('crypto/SCsub')
-SConscript('io/SCsub')
-SConscript('debugger/SCsub')
-SConscript('input/SCsub')
-SConscript('bind/SCsub')
+SConscript("os/SCsub")
+SConscript("math/SCsub")
+SConscript("crypto/SCsub")
+SConscript("io/SCsub")
+SConscript("debugger/SCsub")
+SConscript("input/SCsub")
+SConscript("bind/SCsub")
 
 
 # Build it all as a library

core/bind/SCsub

@@ -1,5 +1,5 @@
 #!/usr/bin/env python
 
-Import('env')
+Import("env")
 
 env.add_source_files(env.core_sources, "*.cpp")