fix: get buck2 working in OSS clone

.buckconfig

@@ -0,0 +1,10 @@
+[cells]
+gh_facebook_sapling = .
+shim_DISABLED = shim
+
+[cell_aliases]
+root = gh_facebook_sapling
+
+[oss]
+internal_cell = fbcode
+project_dirs = eden

.buckconfig.d/common.buckconfig

@@ -0,0 +1,20 @@
+[cells]
+prelude = prelude
+none = none
+
+[cell_aliases]
+config = prelude
+ovr_config = prelude
+bazel_skylib = gh_facebook_buck2_shims_meta
+buck = gh_facebook_buck2_shims_meta
+fbcode = gh_facebook_buck2_shims_meta
+fbcode_macros = gh_facebook_buck2_shims_meta
+fbsource = gh_facebook_buck2_shims_meta
+shim = gh_facebook_buck2_shims_meta
+toolchains = gh_facebook_buck2_shims_meta
+
+[external_cells]
+prelude = bundled
+
+[parser]
+target_platform_detector_spec = target:root//...->prelude//platforms:default target:shim//...->prelude//platforms:default

.buckconfig.d/external_cells/facebook/buck2-shims-meta/external_cell.buckconfig

@@ -0,0 +1,9 @@
+[cells]
+gh_facebook_buck2_shims_meta = gh_facebook_buck2_shims_meta
+
+[external_cells]
+gh_facebook_buck2_shims_meta = git
+
+[external_cell_gh_facebook_buck2_shims_meta]
+git_origin = https://github.com/facebook/buck2-shims-meta.git
+commit_hash = edb600cfbf0b23dd5e6506912d71ada4185d4c45

eden/fs/service/BUCK

@@ -1,4 +1,4 @@
-load("@fbcode//eden:defs.bzl", "get_oss_suffix", "make_rule_compatible_with")
+load("//eden:defs.bzl", "get_oss_suffix", "make_rule_compatible_with")
 load("@fbcode_macros//build_defs:cpp_binary.bzl", "cpp_binary")
 load("@fbcode_macros//build_defs:cpp_library.bzl", "cpp_library")
 load("@fbcode_macros//build_defs:java_binary.bzl", "java_binary")
@@ -68,7 +68,7 @@ cpp_library(
 cpp_binary(
     name = "edenfs",
     srcs = [
-        "facebook/main.cpp",
+        "oss/main.cpp",
     ],
     linker_flags = select({
         "DEFAULT": [],