[Groff] [patch] improve POSIX conformance of src/roff/groff/Makefile.sub

[Ingo Schwarze]

Hi,

the commit message says it all.
Without this, the groff build dies on *BSD with this message:

Using $< in a non-suffix rule context is a GNUmake idiom (Makefile.sub:48)

Yours,
  Ingo


commit c89400010ab2b44414b78a8072e9722f21b9284c
Author: Ingo Schwarze <address@hidden>
Date:   Mon Mar 10 19:43:33 2014 +0100

    Improve POSIX conformance of src/roff/groff/Makefile.sub.
    
    - POSIX says that the meaning of the make(1) $< macro
      shall be unspecified except in inference rules.
      Consequently, use $? for portability.
      That's safe because the rules have only one prerequisite
      and are not .PHONY, so $? will always expand to one item.
    - While here, clean up two instances of useless use of cat(1).

diff --git a/ChangeLog b/ChangeLog
index 2a57001..f935ebd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
 2014-03-10  Ingo Schwarze  <address@hidden>
 
+       * src/roff/groff/Makefile.sub: POSIX conformance
+
+        - POSIX says that the meaning of the make(1) $< macro
+          shall be unspecified except in inference rules.
+          Consequently, use $? for portability.
+          That's safe because the rules have only one prerequisite
+          and are not .PHONY, so $? will always expand to one item.
+        - While here, clean up two instances of useless use of cat(1).
+
+2014-03-10  Ingo Schwarze  <address@hidden>
+
        * Makefile.in: Improve the top-level "make dist" target.
 
         - Bugfix: Do not error out if one of the DISTDIRS
diff --git a/src/roff/groff/Makefile.sub b/src/roff/groff/Makefile.sub
index 0fff2cb..6b56c3d 100644
--- a/src/roff/groff/Makefile.sub
+++ b/src/roff/groff/Makefile.sub
@@ -44,22 +44,20 @@ RM=rm -f
 all: $(srcdir)/groff.cpp groff_opts.tmp $(GROFF_OPTS_OUTPUT)
 
 groff_opts.tmp: $(srcdir)/groff.cpp
-       @$(GREP) -e ':.*:.*:' $< \
+       @$(GREP) -e ':.*:.*:' $? \
                | sed -e 's/[ \t",]//g' > $@
        @echo -n 'groff options: '
        @cat $@
 
 groff_opts_no_arg.txt: groff_opts.tmp
        @$(RM) $@
-       @cat $< \
-               | sed -e 's/[a-zA-Z]://g' > $@
+       @sed -e 's/[a-zA-Z]://g' $? > $@
        @echo -n 'no arg: '
        @cat $@
 
 groff_opts_with_arg.txt: groff_opts_no_arg.txt
        @$(RM) $@
-       @cat groff_opts.tmp \
-               | sed "s/[`cat $<`:]//g" > $@
+       @sed "s/[`cat $?`:]//g" groff_opts.tmp > $@
        @echo -n 'with arg: '
        @cat $@