Blank definition of unused, but referenced variable

Source commit: 11d7efea84fba4afb2481e0752a9ef2e727ff47d

source/core/PuttyIntf.cpp

@@ -12,6 +12,7 @@
 #include <StrUtils.hpp>
 //---------------------------------------------------------------------------
 char sshver[50];
+extern const char commitid[] = "";
 const int platform_uses_x11_unix_by_default = TRUE;
 CRITICAL_SECTION putty_section;
 bool SaveRandomSeed;