build: generate tiles/Makefile from tiles/Makefile.in (rename unit)

First module of the Makefile.in migration (proof).  Pure rename: the
Makefile content is unchanged, so config.status just copies it and the
module still builds via the defs.mak srcdir *derivation* (dual mode from
phase 1) -- the @srcdir@ substitution is a separate follow-up.

* git mv tiles/Makefile -> tiles/Makefile.in
* configure.in: AC_CONFIG_FILES([tiles/Makefile:tiles/Makefile.in]);
  regenerated configure.  config.status now creates build/tiles/Makefile,
  so $(submake) recurses into tiles natively (make -C tiles), no -f.
* .gitignore: ignore the generated tiles/Makefile (in-tree it lands in the
  source tree) -- added in this same commit so it can never be committed.

Verified out-of-tree: config.status writes build/tiles/Makefile,
make -C tiles module builds libtiles.o (rc=0).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -19,7 +19,8 @@ reconfigure.sh
 # "<dir>/Makefile" here in the *same commit*, so an in-tree build never lets a
 # generated Makefile be committed.  (Top-level /Makefile is handled above;
 # readline/ is intentionally NOT converted and keeps its tracked static Makefile.)
-# --- converted dirs below (none yet) ---
+# --- converted dirs below ---
+tiles/Makefile
 
 # Compiled objects / libraries
 *.o

scripts/configure

@@ -9399,6 +9399,9 @@ ac_config_files="$ac_config_files scripts/makedbh:scripts/makedbh.in"
 ac_config_files="$ac_config_files rules.mak:rules.mak"
 
 
+ac_config_files="$ac_config_files tiles/Makefile:tiles/Makefile.in"
+
+
 if test "`cd $srcdir && pwd`" = "`pwd`" ; then
   magic_config_header=magic/autoconf/config.h
 else
@@ -10127,6 +10130,7 @@ do
     "defs.mak") CONFIG_FILES="$CONFIG_FILES defs.mak:scripts/defs.mak.in" ;;
     "scripts/makedbh") CONFIG_FILES="$CONFIG_FILES scripts/makedbh:scripts/makedbh.in" ;;
     "rules.mak") CONFIG_FILES="$CONFIG_FILES rules.mak:rules.mak" ;;
+    "tiles/Makefile") CONFIG_FILES="$CONFIG_FILES tiles/Makefile:tiles/Makefile.in" ;;
 
   *) as_fn_error $? "invalid argument: \`$ac_config_target'" "$LINENO" 5;;
   esac

scripts/configure.in

@@ -2003,6 +2003,10 @@ dnl places it next to the generated defs.mak so a single ${MAGICDIR} resolves
 dnl both `include`s in every subdir Makefile out-of-tree).
 AC_CONFIG_FILES([rules.mak:rules.mak])
 
+dnl Per-module Makefiles (Makefile.in migration).  Each converted module lists
+dnl its Makefile here; config.status creates the build subdir and the Makefile.
+AC_CONFIG_FILES([tiles/Makefile:tiles/Makefile.in])
+
 dnl Emit an autoconf config header, available to the tree as
 dnl   #include <magic/autoconf/config.h>
 dnl It carries every autoconf define (i.e. at least all the -D options that