Dont pass -fPIC flag on Windows (unsupported option)

Author: bellenot

test/CodeGeneration/Symbols.C

@@ -6,7 +6,7 @@
 // LICENSE.TXT for details.
 //------------------------------------------------------------------------------
 
-// RUN: clang -shared -fPIC -DCLING_EXPORT=%dllexport -DBUILD_SHARED %s -o%T/libSymbols%shlibext
+// RUN: clang -shared %fPIC -DCLING_EXPORT=%dllexport -DBUILD_SHARED %s -o%T/libSymbols%shlibext
 // RUN: %cling --nologo -L%T -lSymbols  %s | FileCheck %s
 
 // Check that weak symbols do not get re-emitted (ROOT-6124)

test/lit.cfg

@@ -276,8 +276,10 @@ else:
 
 if platform.system() in ['Windows']:
   config.substitutions.append(('%dllexport', '"__declspec(dllexport)"'))
+  config.substitutions.append(('%fPIC', ''))
 else:
   config.substitutions.append(('%dllexport', ''))
+  config.substitutions.append(('%fPIC', '-fPIC'))
 
 if IsWindows and execute_external:
   config.substitutions.append(('%mkdir', 'mkdir'))