Merge 'build: use default value of --with-* option s' from Kefu Chai

in this series, we use the default values of options specifying the paths to tools for better readability. and also to ease the migration to CMake

Refs #15379

Closes scylladb/scylladb#15500

* github.com:scylladb/scylladb:
  build: do not check for args.ragel_exec
  build: set default value of --with-antlr3 option

configure.py

@@ -751,7 +751,7 @@ arg_parser.add_argument('--enable-alloc-failure-injector', dest='alloc_failure_i
                         help='enable allocation failure injection')
 arg_parser.add_argument('--enable-seastar-debug-allocations', dest='seastar_debug_allocations', action='store_true', default=False,
                         help='enable seastar debug allocations')
-arg_parser.add_argument('--with-antlr3', dest='antlr3_exec', action='store', default=None,
+arg_parser.add_argument('--with-antlr3', dest='antlr3_exec', action='store', default="antlr3",
                         help='path to antlr3 executable')
 arg_parser.add_argument('--with-ragel', dest='ragel_exec', action='store', default='ragel',
         help='path to ragel executable')
@@ -1800,15 +1800,7 @@ else:
 
 os.makedirs(outdir, exist_ok=True)
 
-if args.antlr3_exec:
-    antlr3_exec = args.antlr3_exec
-else:
-    antlr3_exec = "antlr3"
-
-if args.ragel_exec:
-    ragel_exec = args.ragel_exec
-else:
-    ragel_exec = "ragel"
+ragel_exec = args.ragel_exec
 
 
 def write_build_file(f,
@@ -1958,7 +1950,7 @@ def write_build_file(f,
               command = CARGO_BUILD_DEP_INFO_BASEDIR='.' cargo build --locked --manifest-path=rust/Cargo.toml --target-dir=$builddir/{mode} --profile=rust-{mode} $
                         && touch $out
               description = RUST_LIB $out
-            ''').format(mode=mode, antlr3_exec=antlr3_exec, fmt_lib=fmt_lib, test_repeat=test_repeat, test_timeout=test_timeout, **modeval))
+            ''').format(mode=mode, antlr3_exec=args.antlr3_exec, fmt_lib=fmt_lib, test_repeat=test_repeat, test_timeout=test_timeout, **modeval))
         f.write(
             'build {mode}-build: phony {artifacts} {wasms}\n'.format(
                 mode=mode,