Move metaconfig control comments into its own files

MANIFEST

@@ -3919,6 +3919,8 @@ malloc_ctl.h			A version of malloc you might not want
 MANIFEST			This list of files
 mathoms.c			A home for binary-compatible code artifacts
 META.yml			Distribution meta-data in YAML
+metaconfig.h			Control file for the metaconfig process
+metaconfig.SH			Control file for the metaconfig process
 mg.c				Magic code
 mg.h				Magic header
 minimod.pl			Writes lib/ExtUtils/Miniperl.pm

Makefile.SH

@@ -20,23 +20,6 @@ case $CROSS_NAME in
 	;;
 esac
 
-# H.Merijn Brand [17 Feb 2004]
-# This comment is just to ensure that Configure will find variables that
-# are removed/replaced in patches on blead, but are still needed in the
-# 5.8.x, 5.6.x and 5.005.x maintainance tracks.
-# metaconfig -m will scan all .SH files on this level (not deeper), and
-# not in x2p and other subfolders. This file is as good as any .SH
-# patch   references
-# #22227 $baserev
-# #22302 $yacc $byacc
-
-# H.Merijn Brand [30 Oct 2004]
-# Mentioned for the same reason for future reference
-# #23434 $d_strlcat $d_strlcpy
-
-# H.Merijn Brand [21 Dec 2010]
-# cbeaa1895 removed the reference to $perlpath
-
 : This forces SH files to create target in same directory as SH file.
 : This is so that make depend always knows where to find SH derivatives.
 case "$0" in

handy.h

@@ -208,20 +208,6 @@ typedef U64TYPE U64;
 #   endif
 #endif
 
-/* HMB H.Merijn Brand - a placeholder for preparing Configure patches:
- * 
- * USE_DTRACE	HAS_PSEUDOFORK	HAS_TIMEGM	LOCALTIME_R_NEEDS_TZSET	
- * GMTIME_MAX	GMTIME_MIN	LOCALTIME_MAX	LOCALTIME_MIN
- * HAS_CTIME64	HAS_LOCALTIME64	HAS_GMTIME64	HAS_DIFFTIME64
- * HAS_MKTIME64	HAS_ASCTIME64	HAS_GETADDRINFO	HAS_GETNAMEINFO
- * HAS_INETNTOP	HAS_INETPTON	CHARBITS	HAS_PRCTL
- * HAS_SOCKADDR_SA_LEN HAS_SIN6_SCOPE_ID
- * Not (yet) used at top level, but mention them for metaconfig
- */
-
-/* Mention I8SIZE, U8SIZE, I16SIZE, U16SIZE, I32SIZE, U32SIZE,
-   I64SIZE, and U64SIZE here so that metaconfig pulls them in. */
-
 #if defined(UINT8_MAX) && defined(INT16_MAX) && defined(INT32_MAX)
 
 /* I8_MAX and I8_MIN constants are not defined, as I8 is an ambiguous type.

metaconfig.SH

@@ -0,0 +1,32 @@
+#!/bin/sh
+
+# This is a placeholder file for symbols that should be exported
+# into config_h.SH and Porting/Glossary. See also metaconfig.h
+#
+# First version was created from the part in Makefile.SH
+# H.Merijn Brand 21 Dec 2010 (Tux)
+#
+# Mentioned variables are forced to be included into config_h.SH
+# as they are only included if meta finds them referenced. That
+# implies that noone can use them unless they are available and
+# they won't be available unless used. When new symbols are probed
+# in Configure, this is the way to force them into availability.
+
+# H.Merijn Brand [17 Feb 2004]
+# This comment is just to ensure that Configure will find variables that
+# are removed/replaced in patches on blead, but are still needed in the
+# 5.8.x, 5.6.x and 5.005.x maintainance tracks.
+# metaconfig -m will scan all .SH files on this level (not deeper), and
+# not in x2p and other subfolders. This file is as good as any .SH
+# patch   references
+# #22227 $baserev
+# #22302 $yacc $byacc
+
+# H.Merijn Brand [30 Oct 2004]
+# Mentioned for the same reason for future reference
+# #23434 $d_strlcat $d_strlcpy
+
+# H.Merijn Brand [21 Dec 2010]
+# cbeaa1895 removed the reference to $perlpath
+
+1;

metaconfig.h

@@ -0,0 +1,44 @@
+/* This is a placeholder file for symbols that should be exported
+ * into config_h.SH and Porting/Glossary. See also metaconfig.SH
+ *
+ * First version was created from the part in handy.h (which includes this)
+ * H.Merijn Brand 21 Dec 2010 (Tux)
+ *
+ * Mentioned variables are forced to be included into config_h.SH
+ * as they are only included if meta finds them referenced. That
+ * implies that noone can use them unless they are available and
+ * they won't be available unless used. When new symbols are probed
+ * in Configure, this is the way to force them into availability.
+ *
+ * CHARBITS
+ * GMTIME_MAX
+ * GMTIME_MIN
+ * HAS_ASCTIME64
+ * HAS_CTIME64
+ * HAS_DIFFTIME64
+ * HAS_GETADDRINFO
+ * HAS_GETNAMEINFO
+ * HAS_GMTIME64
+ * HAS_INETNTOP
+ * HAS_INETPTON
+ * HAS_LOCALTIME64
+ * HAS_MKTIME64
+ * HAS_PRCTL
+ * HAS_PSEUDOFORK
+ * HAS_SIN6_SCOPE_ID
+ * HAS_SOCKADDR_SA_LEN
+ * HAS_TIMEGM
+ * I16SIZE
+ * I32SIZE
+ * I64SIZE
+ * I8SIZE
+ * LOCALTIME_MAX
+ * LOCALTIME_MIN
+ * LOCALTIME_R_NEEDS_TZSET
+ * U16SIZE
+ * U32SIZE
+ * U64SIZE
+ * U8SIZE
+ * USE_DTRACE
+ *
+ */