mononoke/integration: build EdenSCM with non system OpenSSL (#12)

Summary:
Pull Request resolved: facebookexperimental/rust-shed#12

The OpenSSL version on Mac doesn't work well with EdenSCM and Mononoke integration, just use the one from getdeps/brew.

Also remove the now redundant "DEVELOPER_DIR" since the modern XCode version works.

Pull Request resolved: facebook/sapling#63

Reviewed By: StanislavGlebik

Differential Revision: D23927022

Pulled By: lukaspiatkowski

fbshipit-source-id: 6b6b3baa33d49b567b9aa6178cbd20b7ae9edc89

Author: lukaspiatkowski

build/fbcode_builder/getdeps/buildopts.py

@@ -269,12 +269,11 @@ def compute_env_for_install_dirs(self, install_dirs, env=None, manifest=None):
                 env["RUSTC"] = rustc_path
                 env["RUSTDOC"] = rustdoc_path
 
-            if self.is_windows():
-                libcrypto = os.path.join(d, "lib/libcrypto.lib")
-            else:
-                libcrypto = os.path.join(d, "lib/libcrypto.so")
             openssl_include = os.path.join(d, "include/openssl")
-            if os.path.isfile(libcrypto) and os.path.isdir(openssl_include):
+            if os.path.isdir(openssl_include) and any(
+                os.path.isfile(os.path.join(d, "lib", libcrypto))
+                for libcrypto in ("libcrypto.lib", "libcrypto.so", "libcrypto.a")
+            ):
                 # This must be the openssl library, let Rust know about it
                 env["OPENSSL_DIR"] = d