d3dcompiler: Clear preprocessor lexer state after running it.

dlls/d3dcompiler_43/compiler.c

@@ -475,6 +475,7 @@ int wpp_parse( const char *input, FILE *output )
     }
     /* Clean if_stack, it could remain dirty on errors */
     while (pp_get_if_depth()) pp_pop_if();
+    ppy_lex_destroy();
     del_special_defines();
     del_cmdline_defines();
     pp_pop_define_state();

dlls/d3dcompiler_43/wpp_private.h

@@ -235,6 +235,7 @@ extern includelogicentry_t *pp_includelogiclist;
 extern FILE *ppy_out;
 extern char *ppy_text;
 int ppy_lex(void);
+int ppy_lex_destroy(void);
 
 void pp_do_include(char *fname, int type);
 void pp_push_ignore_state(void);