Best-effort attempt at finding libssl (#1167)

telethon/crypto/libssl.py

@@ -4,12 +4,39 @@ Helper module around the system's libssl library if available for IGE mode.
 import ctypes
 import ctypes.util
 import logging
-
+import os
 
 __log__ = logging.getLogger(__name__)
 
 
 lib = ctypes.util.find_library('ssl')
+
+# This is a best-effort attempt at finding the full real path of lib.
+#
+# Unfortunately ctypes doesn't tell us *where* it finds the library,
+# so we have to do that ourselves.
+try:
+    # This is not documented, so it could fail. Be on the safe side.
+    import ctypes.macholib.dyld
+    paths = ctypes.macholib.dyld.DEFAULT_LIBRARY_FALLBACK
+except (ImportError, AttributeError):
+    paths = [
+        os.path.expanduser("~/lib"),
+        "/usr/local/lib",
+        "/lib",
+        "/usr/lib",
+    ]
+
+for path in paths:
+    if os.path.isdir(path):
+        for root, _, files in os.walk(path):
+            if lib in files:
+                # Manually follow symbolic links on *nix systems.
+                # Fix for https://github.com/LonamiWebs/Telethon/issues/1167
+                lib = os.path.realpath(os.path.join(root, lib))
+                break
+
+
 try:
     if not lib:
         raise OSError('no library called "ssl" found')