edenscm/hg: add GitHub Actions with CI for HG plus add fixes for getdeps (#25)

Summary:
Fixes include:
1. Passing "GETDEPS_BUILD_DIR" and "GETDEPS_INSTALL_DIR" env variable and using them in eden/scm/Makefile rather than assuming the source code is always in the same place regardless getdeps arguments (it isn't).
2. Added "fbthrift-source" and "fb303-source" to avoid unnecessary compilation (at least of fb303) and to put fbthrift and fb303 source code in an easy to locate place inside getdeps' "installed" folder.

Pull Request resolved: https://github.com/facebookexperimental/eden/pull/25

Test Plan: sandcastle, check oss-eden_scm-darwin-getdeps

Reviewed By: farnz

Differential Revision: D22431872

Pulled By: lukaspiatkowski

fbshipit-source-id: 8ccbb090713ec085a5dd56df509eb58ab6fb9e34

build/fbcode_builder/getdeps/builder.py

@@ -990,7 +990,6 @@ class CargoBuilder(BuilderBase):
     def run_cargo(self, install_dirs, operation, args=None):
         args = args or []
         env = self._compute_env(install_dirs)
-        self.add_openssl_to_env(env, install_dirs)
         # Enable using nightly features with stable compiler
         env["RUSTC_BOOTSTRAP"] = "1"
         env["LIBZ_SYS_STATIC"] = "1"
@@ -1002,17 +1001,6 @@ class CargoBuilder(BuilderBase):
         ] + args
         self._run_cmd(cmd, cwd=self.workspace_dir(), env=env)
 
-    def add_openssl_to_env(self, env, install_dirs):
-        openssl_candidates = [d for d in install_dirs if "openssl" in d]
-        if len(openssl_candidates) > 1:
-            raise Exception(
-                "Found more than one candidate for openssl directory: {}.".format(
-                    openssl_candidates
-                )
-            )
-        elif len(openssl_candidates) == 1:
-            env["OPENSSL_DIR"] = openssl_candidates[0]
-
     def build_source_dir(self):
         return os.path.join(self.build_dir, "source")