Still need to #define inline for MSVC

I only tested with VS2015 earlier, but previous versions apparently still
don't know that standard C99 keyword though it's documented on MSDN...
diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index c8a320c..c21e0a0 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -32,9 +32,9 @@
 
 #include <string.h>
 
-#if defined(__ARMCC_VERSION) && !defined(inline)
+#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && !defined(inline)
 #define inline __inline
-#endif /* __ARMCC_VERSION */
+#endif
 
 /*
  * Conversion macros for embedded constants: