ivlpp - clear lexor dynamic state information for flex >= 2.5.9

For flex version 2.5.9 and later there is a function
"yylex_destroy()" that clears any space dynamically
allocated by the scanner.

ivlpp/globals.h

@@ -22,6 +22,7 @@
 # include  <stdio.h>
 
 extern void reset_lexor(FILE*out, char*paths[]);
+extern void destroy_lexor();
 extern void load_precompiled_defines(FILE*src);
 extern void define_macro(const char*name, const char*value, int keyword,
                          int argc);

ivlpp/lexor.lex

@@ -1803,3 +1803,17 @@ void reset_lexor(FILE* out, char* paths[])
         tail = isp;
     }
 }
+
+/*
+ * Modern version of flex (>=2.5.9) can clean up the scanner data.
+ */
+void destroy_lexor()
+{
+# ifdef FLEX_SCANNER
+#   if YY_FLEX_MAJOR_VERSION >= 2 && YY_FLEX_MINOR_VERSION >= 5
+#     if defined(YY_FLEX_SUBMINOR_VERSION) && YY_FLEX_SUBMINOR_VERSION >= 9
+    yylex_destroy();
+#     endif
+#   endif
+# endif
+}

ivlpp/main.c

@@ -370,6 +370,7 @@ int main(int argc, char*argv[])
 	   start scanning. */
       reset_lexor(out, source_list);
       if (yylex()) return -1;
+      destroy_lexor();
 
       if(depend_file) {
 	      fclose(depend_file);