gh-140550: Fix PyABIInfo_VAR macro: avoid ";"

Remove ";" from PyABIInfo_VAR macro definition, since
"PyABIInfo_VAR(abi_info);" added two ";;" which is illegal in C++03.

Author: vstinner

Include/modsupport.h

@@ -140,7 +140,7 @@ PyAPI_FUNC(int) PyABIInfo_Check(PyABIInfo *info, const char *module_name);
     /////////////////////////////////////////////////////////
 
 #define PyABIInfo_VAR(NAME) \
-    static PyABIInfo NAME = _PyABIInfo_DEFAULT;
+    static PyABIInfo NAME = _PyABIInfo_DEFAULT
 
 #undef _PyABIInfo_DEFAULT_STABLE
 #undef _PyABIInfo_DEFAULT_FT