lib/asn1: WIN32 suppress "unreferenced local variable" warning

the code generated by asn1_compile.exe includes a large number
of unreferenced local variables.  The resulting warnings drown
out other potentially more serious warnings.

This change suppresses the C4101 warnings in the generated
source files.

Change-Id: I17642ff427f457c885b1eb0e62436f3bc9057ee1

lib/asn1/gen.c

@@ -388,6 +388,9 @@ generate_header_of_codefile(const char *name)
 	fprintf (codefile,
 		 "#include <parse_units.h>\n\n");
 
+#ifdef _WIN32
+    fprintf(codefile, "#pragma warning(disable: 4101)\n\n");
+#endif
 }
 
 void