More reliably find mscorlib.dll on Linux

modules/mono/config.py

@@ -2,6 +2,7 @@
 import imp
 import os
 import sys
+import subprocess
 
 from SCons.Script import BoolVariable, Dir, Environment, PathVariable, Variables
 
@@ -150,6 +151,8 @@ def configure(env):
                     raise RuntimeError('Could not find mono shared library in: ' + mono_lib_path)
 
                 copy_file(mono_lib_path, 'bin', 'lib' + mono_so_name + sharedlib_ext)
+
+            copy_file(os.path.join(mono_lib_path, 'mono', '4.5'), assemblies_output_dir, 'mscorlib.dll')
         else:
             if mono_static:
                 raise RuntimeError('mono-static: Not supported with pkg-config. Specify a mono prefix manually')
@@ -158,6 +161,7 @@ def configure(env):
 
             mono_lib_path = ''
             mono_so_name = ''
+            mono_prefix = subprocess.check_output(["pkg-config", "mono-2", "--variable=prefix"]).strip()
 
             tmpenv = Environment()
             tmpenv.AppendENVPath('PKG_CONFIG_PATH', os.getenv('PKG_CONFIG_PATH'))
@@ -174,8 +178,7 @@ def configure(env):
                 raise RuntimeError('Could not find mono shared library in: ' + str(tmpenv['LIBPATH']))
 
             copy_file(mono_lib_path, 'bin', 'lib' + mono_so_name + sharedlib_ext)
-
-        copy_file(os.path.join(mono_lib_path, 'mono', '4.5'), assemblies_output_dir, 'mscorlib.dll')
+            copy_file(os.path.join(mono_prefix, 'lib', 'mono', '4.5'), assemblies_output_dir, 'mscorlib.dll')
 
         env.Append(LINKFLAGS='-rdynamic')