Patch to find libstdc++.

https://bugs.funtoo.org/browse/FL-3519
--- a/bin/mendeleydesktop
+++ b/bin/mendeleydesktop
@@ -29,6 +29,13 @@ def library_paths():
     paths.append("/usr/lib/x86_64-linux-gnu")
     paths.append("/usr/lib/i386-linux-gnu")
 
+    gcc_libpath = subprocess.Popen(
+        '/usr/bin/gcc-config -L', shell=True, stdout=subprocess.PIPE,
+    ).stdout.read().decode('utf-8').replace('\n', '').split(':')
+    for path in gcc_libpath:
+        if len(path) > 0:
+            paths.append(path)
+
     return paths
 
 def library_version_from_path(lib_path):