master 7c8a131984: Display a help message when building Emacs failed.

[Gregory Heytings]

branch: master
commit 7c8a131984ab47349381975dead1712ae25ae2c6
Author: Gregory Heytings <gregory@heytings.org>
Commit: Gregory Heytings <gregory@heytings.org>

    Display a help message when building Emacs failed.
    
    * Makefile.in (actual-all): New target, replacing the former 'all'
    target.
    (advice-on-failure, sanity-check): New targets.
    (all): Use the new targets.
    (bootstrap-all): New target, identical to 'all' but meant for the
    'bootstrap' target in GNUmakefile.
    (actual-bootstrap): New target, replacing the former 'bootstrap'
    target.  Use the 'actual-all' target instead of the 'all' target.
    (bootstrap): Use the new targets.
    
    * GNUmakefile (bootstrap): Use the new 'bootstrap-all' target.
---
 GNUmakefile |  2 +-
 Makefile.in | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 60 insertions(+), 5 deletions(-)

diff --git a/GNUmakefile b/GNUmakefile
index 8eb61dc0ad..05edbe099b 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -115,7 +115,7 @@ endif
 
 # 'make bootstrap' in a fresh checkout needn't run 'configure' twice.
 bootstrap: Makefile
-       $(MAKE) -f Makefile all
+       $(MAKE) -f Makefile bootstrap-all
 
 .PHONY: bootstrap default $(ORDINARY_GOALS)
 
diff --git a/Makefile.in b/Makefile.in
index 3f811ea60f..de263c6858 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -366,7 +366,58 @@ endif
 
 gsettings_SCHEMAS = etc/org.gnu.emacs.defaults.gschema.xml
 
-all: ${SUBDIR} info $(gsettings_SCHEMAS:.xml=.valid) src-depending-on-lisp
+all:
+       $(MAKE) actual-all || $(MAKE) advice-on-failure make-target=all 
exit-status=$$?
+       $(MAKE) sanity-check make-target=all
+
+# This target is used by the 'bootstrap' target in GNUmakefile, instead of 
'all'.
+bootstrap-all:
+       $(MAKE) actual-all || $(MAKE) advice-on-failure make-target=bootstrap 
exit-status=$$?
+       $(MAKE) sanity-check make-target=bootstrap
+
+.PHONY: bootstrap-all actual-all advice-on-failure sanity-check
+
+actual-all: ${SUBDIR} info $(gsettings_SCHEMAS:.xml=.valid) 
src-depending-on-lisp
+
+# ADVICE-ON-FAILURE-BEGIN:all
+#   You might try to:
+#   - run "make bootstrap", which might fix the problem
+#   - run "make V=1", which displays the full commands invoked by make,
+#     to further investigate the problem
+# ADVICE-ON-FAILURE-END:all
+
+# ADVICE-ON-FAILURE-BEGIN:bootstrap
+#   You might try to:
+#   - run "git clean -fdx" and run "make bootstrap" again, which might
+#     fix the problem
+#     !BEWARE! "git clean -fdx" deletes all files that are not under
+#     !BEWARE! version control, which means that all changes to such
+#     !BEWARE! files will be lost and cannot be restored later
+#   - run "make V=1", which displays the full commands invoked by make,
+#     to further investigate the problem
+# ADVICE-ON-FAILURE-END:bootstrap
+
+advice-on-failure:
+       @echo
+       @echo "  \"make ${make-target}\" failed with exit status 
${exit-status}."
+       @cat Makefile | \
+         sed -n '/^# ADVICE-ON-FAILURE-BEGIN:${make-target}/,$${p;/^# 
ADVICE-ON-FAILURE-END:${make-target}/q};' | \
+         sed 's/^# //' | grep -v '^ADVICE-ON-FAILURE-'
+       @echo
+       @exit ${exit-status}
+
+sanity-check:
+       @v=$$(src/emacs${EXEEXT} --batch --eval \
+         '(progn (defun f (n) (if (= 0 n) 1 (* n (f (- n 1))))) (princ (f 
10)))' \
+         2> /dev/null); \
+       [ "X$$v" == "X3628800" ] && exit 0; \
+       echo; \
+       echo "  \"make ${make-target}\" succeeded, but Emacs is not 
functional."; \
+       cat Makefile | \
+         sed -n '/^# ADVICE-ON-FAILURE-BEGIN:${make-target}/,$${p;/^# 
ADVICE-ON-FAILURE-END:${make-target}/q};' | \
+         sed 's/^# //' | grep -v '^ADVICE-ON-FAILURE-'; \
+       echo; \
+       exit 1
 
 .PHONY: all ${SUBDIR} blessmail epaths-force epaths-force-w32 
epaths-force-ns-self-contained etc-emacsver
 
@@ -1170,7 +1221,11 @@ check-info: info
 ### This first cleans the lisp subdirectory, removing all compiled
 ### Lisp files.  Then re-run make to build all the files anew.
 
-.PHONY: bootstrap
+.PHONY: bootstrap actual-bootstrap
+
+bootstrap:
+       $(MAKE) actual-bootstrap || $(MAKE) advice-on-failure 
make-target=bootstrap exit-status=$$?
+       $(MAKE) sanity-check make-target=bootstrap
 
 # Without a 'configure' variable, bootstrapping does the following:
 #  * Remove files to start from a bootstrap-clean slate.
@@ -1181,7 +1236,7 @@ check-info: info
 #  * Remove files to start from an extraclean slate.
 #  * Do the actual build, during which the 'configure' variable is
 #    used (see the Makefile goal in GNUmakefile).
-bootstrap:
+actual-bootstrap:
 ifndef configure
        $(MAKE) bootstrap-clean
        cd $(srcdir) && ./autogen.sh autoconf
@@ -1189,7 +1244,7 @@ ifndef configure
 else
        $(MAKE) extraclean
 endif
-       $(MAKE) all
+       $(MAKE) actual-all
 
 .PHONY: ChangeLog change-history change-history-commit change-history-nocommit
 .PHONY: preferred-branch-is-current unchanged-history-files