Revert "Minimize the changes in #5277"

This reverts commit dc51d89ac2.

include/mruby/presym.h

@@ -9,9 +9,7 @@
 
 #if defined(MRB_NO_PRESYM)
 # include <mruby/presym/disable.h>
-#elif defined(MRB_PRESYM_SCANNING)
-# include <mruby/presym/scanning.h>
-#else
+#elif !defined(MRB_PRESYM_SCANNING)
 # include <mruby/presym/enable.h>
 #endif
 

include/mruby/presym.inc

@@ -1,12 +0,0 @@
-/**
-** @file mruby/presym.inc - Fallback file for Preallocated Symbols
-**
-** See Copyright Notice in mruby.h
-*/
-
-/*
- * Reading this file means you failed to specify `-I<build-dir>/include`
- * in the configuration. I will not use `PRESYM*` macros for compilation.
- */
-
-#define MRB_NO_PRESYM

include/mruby/presym/enable.h

@@ -8,20 +8,6 @@
 #define MRUBY_PRESYM_ENABLE_H
 
 #undef MRB_PRESYM_MAX
-#define MRB_PRESYM_NAMED(lit, num, type, name)
-#define MRB_PRESYM_UNNAMED(lit, num)
-/* test for proper -I `<build-dir>/include` */
-/* fallback `presym.inc` defines `MRB_NO_PRESYM` */
-# include <mruby/presym.inc>
-
-#undef MRB_PRESYM_MAX
-#undef MRB_PRESYM_NAMED
-#undef MRB_PRESYM_UNNAMED
-
-#if defined(MRB_NO_PRESYM)
-# include <mruby/presym/disable.h>
-#else
-
 #define MRB_PRESYM_NAMED(lit, num, type, name) MRB_##type##__##name = (num),
 #define MRB_PRESYM_UNNAMED(lit, num)
 
@@ -52,6 +38,4 @@ enum mruby_presym {
   static const mrb_sym name[] = {__VA_ARGS__};                                \
   static void init_##name(mrb_state *mrb) {}
 
-#endif  /* !MRUBY_NO_PRESYM */
-
 #endif  /* MRUBY_PRESYM_ENABLE_H */