Merge pull request #643 from yukawa/fix_win_unicode_build

Fix build failure on Windows when Unicode build is enabled.
diff --git a/src/google/protobuf/compiler/command_line_interface.cc b/src/google/protobuf/compiler/command_line_interface.cc
index c57cfd3..e887186 100644
--- a/src/google/protobuf/compiler/command_line_interface.cc
+++ b/src/google/protobuf/compiler/command_line_interface.cc
@@ -189,7 +189,7 @@
 bool GetProtocAbsolutePath(string* path) {
 #ifdef _WIN32
   char buffer[MAX_PATH];
-  int len = GetModuleFileName(NULL, buffer, MAX_PATH);
+  int len = GetModuleFileNameA(NULL, buffer, MAX_PATH);
 #elif __APPLE__
   char buffer[PATH_MAX];
   int len = 0;