Don't declare snprintf macro for MSVC 2015 and 2017 in lv2/CMakeLists.txt

That declaring breaks build on MSVC 2015/17 (2013 is ok). There is a note about
changed behaviour of snprintf beginning from VS 2015 here:
https://docs.microsoft.com/ru-ru/cpp/c-runtime-library/reference/snprintf-snprintf-snprintf-l-snwprintf-snwprintf-l?view=vs-2017#remarks

cmake-proxies/lv2/CMakeLists.txt

@@ -69,12 +69,14 @@ ${LIB_SRC_DIRECTORY}lv2/suil/src/suil_instance.c
 # This defines the #define on both Windows and Linux.
 add_definitions(
 -D_LIB
--Dsnprintf=_snprintf
 -Dinline=__inline # Not needed in non CMake version.
 -DHAVE_FMAX
 -DLILV_INTERNAL
 -D_DEBUG
  )
+if( NOT MSVC OR MSVC_VERSION LESS 1900 )
+    add_definitions(-Dsnprintf=_snprintf)
+endif()
 add_library( ${TARGET} STATIC ${SOURCES})
 add_compile_options(/TP)
 target_include_directories( ${TARGET} PRIVATE