build: top Makefile.in + build-dir orchestration (out-of-tree)

Make a plain `make` in a build directory build every module into the
build tree.  The top Makefile becomes a configure-generated Makefile.in,
and each recursion drives a build subdirectory (created on demand) using
the module Makefile from the source tree.

Makefile -> Makefile.in (config.status generates Makefile in the build
top via AC_CONFIG_FILES([Makefile:Makefile.in])):
* Add MAGICSRC = @abs_top_srcdir@; read VERSION and re-run configure from
  ${MAGICSRC}.
* Every descent `(cd $$dir && ${MAKE} <goal>)` and `${MAKE} -C $(dir $@)
  <goal>` becomes:
      mkdir -p <builddir> && ${MAKE} -C <builddir> \
              -f ${MAGICSRC}/<dir>/Makefile <goal>
  so the build subdir need not pre-exist and the source Makefile is used.
  Applied to modules/libs/depend pattern rules and the
  tcllibrary/mains/techs/install/clean loops.
* database/database.h: generate from ${MAGICSRC}/.../database.h.in into
  the build tree (mkdir -p database), via the generated build-tree
  ${MAGICDIR}/scripts/makedbh.
* install-dirs/install-tcl-dirs use ${SCRIPTS}/mkdirs (now source-tree);
  clean skips absent build subdirs; distclean/dist/tags updated for the
  split source/build layout.

scripts/defs.mak.in:
* SCRIPTS now points at the source tree (${MAGICSRC}/scripts) for the
  static helpers (mkdirs, printmans, ...); the one generated helper,
  makedbh, is referenced directly at ${MAGICDIR}/scripts (build tree).
* Guard VPATH so it is set only inside module subdirectories, never at
  the build top -- a top-level VPATH into the source tree could let a
  stale source database/database.h shadow the build-tree copy.

scripts/configure.in: AC_CONFIG_FILES([Makefile:Makefile.in]); regenerated
scripts/configure.

Verified out-of-tree: `../configure && make modules && make libs` builds
all 33 module libraries (lib*.o and lib*.a) plus the generated
database/database.h into the build tree, with no errors and the source
tree left clean.  A full `make` (link the magic program, build techs)
still needs the later outlier fixes (magic/, scmos/, ...).

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

Makefile.in

@@ -3,6 +3,11 @@
 #
 
 MAGICDIR   = .
+# Absolute path to the source tree (config.status substitutes @abs_top_srcdir@).
+# For an in-tree build this is the same directory as the build top.  Every
+# recursion below drives a build subdirectory (created on demand) using the
+# module Makefile from the source tree: -C <builddir> -f ${MAGICSRC}/<dir>/Makefile.
+MAGICSRC   = @abs_top_srcdir@
 PROGRAMS   = magic
 TECHS      = scmos
 LIBRARIES  = database utils extflat
@@ -11,7 +16,7 @@ MODULES    = bplane cmwind commands database dbwind debug drc extflat \
 	     utils windows wiring
 
 # This was `cat VERSION`
-VERSION    := $(shell cat ${MAGICDIR}/VERSION)
+VERSION    := $(shell cat ${MAGICSRC}/VERSION)
 
 MAKEFLAGS  =
 INSTALL_CAD_DIRS = windows doc ${TECHS}
@@ -33,21 +38,23 @@ defs.mak:
 	@exit 1
 
 config:
-	${MAGICDIR}/configure
+	${MAGICSRC}/configure
 
 tcllibrary: database/database.h modules
 	@echo --- making Tcl shared libraries
 	for dir in ${PROGRAMS}; do \
-		(cd $$dir && ${MAKE} tcl-main) || exit 1; done
+		mkdir -p $$dir && ${MAKE} -C $$dir -f ${MAGICSRC}/$$dir/Makefile tcl-main || exit 1; done
 
 mains: database/database.h modules libs
 	@echo --- making main programs
 	for dir in ${PROGRAMS}; do \
-		(cd $$dir && ${MAKE} main) || exit 1; done
+		mkdir -p $$dir && ${MAKE} -C $$dir -f ${MAGICSRC}/$$dir/Makefile main || exit 1; done
 
-database/database.h: ${MAGICDIR}/database/database.h.in
+# makedbh is the one generated helper script; it lives in the *build* tree.
+database/database.h: ${MAGICSRC}/database/database.h.in
 	@echo --- making header file database/database.h
-	${SCRIPTS}/makedbh ${MAGICDIR}/database/database.h.in database/database.h
+	@mkdir -p database
+	${MAGICDIR}/scripts/makedbh ${MAGICSRC}/database/database.h.in database/database.h
 
 # tiles xyz => tiles/libtiles.o xyz/libxyz.o
 MODULES_SUBDIR := $(shell for i in ${MODULES}; do echo "$${i}/lib$${i}.o"; done)
@@ -56,13 +63,13 @@ LIBS_SUBDIR := $(shell for i in ${MODULES}; do echo "$${i}/lib$${i}.a"; done)
 
 .PHONY: FORCE
 ${MODULES_SUBDIR}: FORCE
-	@${MAKE} -C $(dir $@) module
+	@d=$(dir $@); mkdir -p $$d && ${MAKE} -C $$d -f ${MAGICSRC}/$${d}Makefile module
 
 .PHONY: modules
 modules: database/database.h depend ${MODULES_SUBDIR}
 
 ${LIBS_SUBDIR}: FORCE
-	@${MAKE} -C $(dir $@) lib
+	@d=$(dir $@); mkdir -p $$d && ${MAKE} -C $$d -f ${MAGICSRC}/$${d}Makefile lib
 
 # Force the tiles/utils modules to exist first for libdatabase.a
 .PHONY: libs
@@ -85,7 +92,7 @@ SUBDIRS_DEPEND = $(addsuffix /Depend, ${SUBDIRS_FILTERED})
 
 ${SUBDIRS_DEPEND}: database/database.h
 	@echo --- making dependencies
-	${MAKE} -C $(dir $@) depend
+	@d=$(dir $@); mkdir -p $$d && ${MAKE} -C $$d -f ${MAGICSRC}/$${d}Makefile depend
 
 .PHONY: depend
 depend: defs.mak ${SUBDIRS_DEPEND}
@@ -94,7 +101,7 @@ depend: defs.mak ${SUBDIRS_DEPEND}
 techs: depend
 	@echo --- making techs
 	for dir in ${TECHS}; do \
-		(cd $$dir && ${MAKE} all) || exit 1; done
+		mkdir -p $$dir && ${MAKE} -C $$dir -f ${MAGICSRC}/$$dir/Makefile all || exit 1; done
 
 install: $(INSTALL_TARGET)
 
@@ -105,17 +112,17 @@ install-magic:
 
 install-real: install-dirs
 	for dir in ${INSTALL_CAD_DIRS}; do \
-		(cd $$dir && ${MAKE} install); done
+		mkdir -p $$dir && ${MAKE} -C $$dir -f ${MAGICSRC}/$$dir/Makefile install; done
 	for dir in ${PROGRAMS}; do \
-		(cd $$dir && ${MAKE} install); done
+		mkdir -p $$dir && ${MAKE} -C $$dir -f ${MAGICSRC}/$$dir/Makefile install; done
 
 install-tcl-dirs:
-	${MAGICDIR}/scripts/mkdirs $(DESTDIR)${INSTALL_BINDIR} \
+	${SCRIPTS}/mkdirs $(DESTDIR)${INSTALL_BINDIR} \
 	$(DESTDIR)${INSTALL_MANDIR} $(DESTDIR)${INSTALL_SYSDIR} \
 	$(DESTDIR)${INSTALL_TCLDIR} $(DESTDIR)${INSTALL_TCLDIR}/bitmaps
 
 install-dirs:
-	${MAGICDIR}/scripts/mkdirs $(DESTDIR)${INSTALL_BINDIR} \
+	${SCRIPTS}/mkdirs $(DESTDIR)${INSTALL_BINDIR} \
 	$(DESTDIR)${INSTALL_MANDIR} $(DESTDIR)${INSTALL_SYSDIR} \
 	$(DESTDIR)${INSTALL_SCMDIR}
 
@@ -126,19 +133,22 @@ install-tcl:
 
 install-tcl-real: install-tcl-dirs
 	for dir in ${INSTALL_CAD_DIRS} ${PROGRAMS}; do \
-		(cd $$dir && ${MAKE} install-tcl); done
+		mkdir -p $$dir && ${MAKE} -C $$dir -f ${MAGICSRC}/$$dir/Makefile install-tcl; done
 
 clean:
 	for dir in ${SUBDIRS_FILTERED} ${TECHS} ${BUNDLED_MODULES}; do \
-		(cd $$dir && ${MAKE} clean); done
+		test -d $$dir && ${MAKE} -C $$dir -f ${MAGICSRC}/$$dir/Makefile clean || true; done
 	${RM} *.tmp */*.tmp *.sav */*.sav *.log TAGS tags
 
 distclean:
 	touch defs.mak
 	@${MAKE} clean
-	${RM} defs.mak old.defs.mak ${MAGICDIR}/scripts/defs.mak
+	# NB: do NOT remove rules.mak here.  In-tree (build == source) it is the
-	${RM} ${MAGICDIR}/scripts/default.conf
+	# tracked source file, not a generated one; out-of-tree the build dir is
-	${RM} ${MAGICDIR}/scripts/config.log ${MAGICDIR}/scripts/config.status
+	# disposable, so leaving its generated copy is harmless.
+	${RM} defs.mak old.defs.mak
+	${RM} scripts/makedbh scripts/default.conf
+	${RM} config.log config.status
 	${RM} database/database.h
 	${RM} scripts/magic.spec magic-${VERSION} magic-${VERSION}.tgz
 	${RM} *.log
@@ -146,7 +156,7 @@ distclean:
 dist:
 	${RM} scripts/magic.spec magic-${VERSION} magic-${VERSION}.tgz
 	${SED} -e /@VERSION@/s%@VERSION@%${VERSION}% \
-	    scripts/magic.spec.in > scripts/magic.spec
+	    ${MAGICSRC}/scripts/magic.spec.in > scripts/magic.spec
 	${LN} -nsf . magic-${VERSION}
 	tar zchvf magic-${VERSION}.tgz --exclude CVS \
 	    --exclude magic-${VERSION}/magic-${VERSION} \
@@ -155,15 +165,15 @@ dist:
 
 clean-mains:
 	for dir in ${PROGRAMS}; do \
-		(cd $$dir && ${RM} $$dir); done
+		${RM} $$dir/$$dir; done
 
 tags:
 	${RM} tags
-	find . ${MODULES} ${PROGRAMS} -name "*.[ch]" -maxdepth 1 | xargs ctags -o tags
+	cd ${MAGICSRC} && find . ${MODULES} ${PROGRAMS} -name "*.[ch]" -maxdepth 1 | xargs ctags -o $(CURDIR)/tags
 
 TAGS:
 	${RM} TAGS
-	find . ${MODULES} ${PROGRAMS} -name "*.[ch]" -maxdepth 1 | xargs etags -o TAGS
+	cd ${MAGICSRC} && find . ${MODULES} ${PROGRAMS} -name "*.[ch]" -maxdepth 1 | xargs etags -o $(CURDIR)/TAGS
 
 setup-git:
 	git config --local include.path ../.gitconfig

scripts/configure

@@ -9296,6 +9296,8 @@ MAKE_CAIRO=$usingCairo
 MAKE_READLINE=$use_bundled_readline
 
 
+ac_config_files="$ac_config_files Makefile:Makefile.in"
+
 ac_config_files="$ac_config_files defs.mak:scripts/defs.mak.in"
 
 ac_config_files="$ac_config_files scripts/makedbh:scripts/makedbh.in"
@@ -10009,6 +10011,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 for ac_config_target in $ac_config_targets
 do
   case $ac_config_target in
+    "Makefile") CONFIG_FILES="$CONFIG_FILES Makefile:Makefile.in" ;;
     "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" ;;

scripts/configure.in

@@ -1980,6 +1980,7 @@ dnl Name the .in templates explicitly (relative to srcdir) so config.status can
 dnl find them when run from a separate build directory.  Outputs land in the
 dnl build directory (config.status' CWD): defs.mak at the build top, makedbh
 dnl under build/scripts/ (matching ${SCRIPTS}/makedbh = ${MAGICDIR}/scripts).
+AC_CONFIG_FILES([Makefile:Makefile.in])
 AC_CONFIG_FILES([defs.mak:scripts/defs.mak.in])
 AC_CONFIG_FILES([scripts/makedbh:scripts/makedbh.in], [chmod +x scripts/makedbh])
 dnl Copy rules.mak into the build top (it has no @...@ substitutions; this just

scripts/defs.mak.in

@@ -26,7 +26,12 @@ BUILD_TOP              := $(abspath $(MAGICDIR))
 # this cannot mis-fire if BUILD_TOP happens to recur later in the path.
 MODULE_SUBPATH         := $(patsubst $(BUILD_TOP)%,%,$(CURDIR))
 srcdir                 := $(MAGICSRC)$(MODULE_SUBPATH)
+# Only set VPATH inside a module (sub)directory, never at the build top: a
+# top-level VPATH into the source tree could let a stale source-tree
+# database/database.h shadow the copy we must (re)generate in the build tree.
+ifneq ($(MODULE_SUBPATH),)
 VPATH                  := $(srcdir)
+endif
 # --------------------------------------------------------------------------
 
 prefix = @prefix@
@@ -35,7 +40,9 @@ bindir = @bindir@
 libdir = @libdir@
 mandir = @mandir@
 
-SCRIPTS		       = ${MAGICDIR}/scripts
+# Source-tree helper scripts (mkdirs, printmans, preproc.py, ...).  The one
+# generated script, makedbh, lives in the *build* tree at ${MAGICDIR}/scripts.
+SCRIPTS		       = ${MAGICSRC}/scripts
 
 INSTALL = @INSTALL@
 INSTALL_PROGRAM = @INSTALL_PROGRAM@