subdirmk: Change stub force target to `run-main.mk'

This produces significantly better error messages:
  [some error from actual makefiles]
  make[1]: Leaving directory '/home/ian/wherever'
  Makefile:6: recipe for target 'run-main.mk' failed

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/generate b/generate
index 178754614ea417bcf9e4d319482615f93dd55a5d..dd22146339b130fc6ffbb7efdd9ab3ce0ccc8515 100755 (executable)
--- a/generate
+++ b/generate
@@ -99,12 +99,12 @@ sub write_makefile ($$) {
     my $cd = $depth ? join('/', ('..',) x $depth) : '.';
     o <<END;
 default: all
     my $cd = $depth ? join('/', ('..',) x $depth) : '.';
     o <<END;
 default: all

-\$(MAKECMDGOALS) all: FORCE-ALWAYS-RUN
+\$(MAKECMDGOALS) all: run-main.mk

        \@:
        \@:

-Makefile FORCE-ALWAYS-RUN:
+Makefile run-main.mk:

        \$(MAKE) -C $cd -f main.mk \$(addprefix ${dir_prefix},\$(or \$(MAKECMDGOALS),all))
 .SUFFIXES:
        \$(MAKE) -C $cd -f main.mk \$(addprefix ${dir_prefix},\$(or \$(MAKECMDGOALS),all))
 .SUFFIXES:

-.PHONY:        FORCE-ALWAYS-RUN
+.PHONY:        run-main.mk

 END
 }
 
 END
 }