Use onbld mandoc.

*** 8,51 ****
  # source.  A copy of the CDDL is also available via the Internet at
  # http://www.illumos.org/license/CDDL.
  #
  
  #
! # Copyright 2012 Nexenta Systems, Inc.  All rights reserved.
  # Copyright 2014 Garrett D'Amore <garrett@damore.org>
  #
  
  PROGS=          mandoc mandoc_preconv
- mandoc_OBJS =   arch.o att.o chars.o eqn.o eqn_html.o eqn_term.o        \
-                 html.o lib.o main.o man.o man_hash.o man_html.o         \
-                 man_macro.o man_term.o man_validate.o mandoc.o mdoc.o   \
-                 mdoc_argv.o mdoc_hash.o mdoc_html.o mdoc_macro.o        \
-                 mdoc_man.o mdoc_term.o mdoc_validate.o msec.o out.o     \
-                 read.o roff.o st.o tbl.o tbl_data.o tbl_html.o          \
-                 tbl_layout.o tbl_opts.o tbl_term.o term.o term_ascii.o  \
-                 term_ps.o tree.o vol.o
  
- preconv_OBJS =  preconv.o
- 
- # We place preconv in /usr/lib.  This is done to avoid conflicting with
- # GNU groff, which puts it into /usr/bin.  We also rename it so that it
- # will only be seen by mandoc -- it isn't intended for general end-user use.
- 
  ROOTPROGS =     $(ROOTBIN)/mandoc $(ROOTLIB)/mandoc_preconv
  
  OBJS=           $(preconv_OBJS) $(mandoc_OBJS)
  
  include         $(SRC)/cmd/Makefile.cmd
  
- CFLAGS +=       $(CC_VERBOSE)
- 
- CPPFLAGS +=     -DHAVE_CONFIG_H -DUSE_WCHAR     \
-                 -DOSNAME="\"illumos\""  \
-                 -DVERSION="\"1.12.1\""
- 
- .KEEP_STATE:
- 
  all:            $(PROGS)
  
  mandoc_preconv: $(preconv_OBJS)
                  $(LINK.c) $(preconv_OBJS) -o $@ $(LDLIBS)
                  $(POST_PROCESS)
--- 8,30 ----
  # source.  A copy of the CDDL is also available via the Internet at
  # http://www.illumos.org/license/CDDL.
  #
  
  #
! # Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
  # Copyright 2014 Garrett D'Amore <garrett@damore.org>
  #
  
  PROGS=          mandoc mandoc_preconv
  
  ROOTPROGS =     $(ROOTBIN)/mandoc $(ROOTLIB)/mandoc_preconv
  
  OBJS=           $(preconv_OBJS) $(mandoc_OBJS)
  
  include         $(SRC)/cmd/Makefile.cmd
+ include         $(SRC)/cmd/mandoc/Makefile.common
  
  all:            $(PROGS)
  
  mandoc_preconv: $(preconv_OBJS)
                  $(LINK.c) $(preconv_OBJS) -o $@ $(LDLIBS)
                  $(POST_PROCESS)