[wing] Fix typo externing methods

[Ignacio Casal Quinteiro <icq src gnome org>]

commit 943f23c90010d17a44712ccbca8d2e720da767ab
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Thu Apr 14 08:15:53 2016 +0200

    Fix typo externing methods

 nmake/config-msvc.mak |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/nmake/config-msvc.mak b/nmake/config-msvc.mak
index b7aae6e..c8a5e01 100644
--- a/nmake/config-msvc.mak
+++ b/nmake/config-msvc.mak
@@ -41,4 +41,4 @@ EXTRA_TARGETS =
 WING_TESTS = \
        $(CFG)\$(PLAT)\named-pipes.exe
 
-WING_LIB_CFLAGS = $(WING_CFLAGS) /DWING_EXTERN="__declspec (dllexport) extern"
+WING_LIB_CFLAGS = $(WING_CFLAGS) /D_WING_EXTERN="__declspec (dllexport) extern"