Imake and DLLs under Cygwin

[Richard]

I have an application which I've successfully rebuilt on Solaris. 
It was configured with imake.
I now have a requirement to port it to Cygwin.  Using the imake
from my X11 distribution there have been various errors due to the Cygwin
configuration files (cygwin.tmpl, cygwin.rules ... in X11R6.4/lib/X11/config)
being somewhat out-of-date, but these have been solved.
The problem comes with the attempt to produce a 'shared library' (DLL
on Cygwin of course).  The Imakefile uses the imake rule SharedLibraryTarget(...):
---------------------------
#define SharedLibraryTarget(libname,rev,solist,down,up)                
@@\
AllTarget(Concat3(lib,libname,.dll))                                   
@@\
         @@\
CppFileTarget(libname.def,libname-def.cpp,-DLIBRARY_VERSION=rev,$(ICONFIGFILES))
@@\
---------------------------
which produces the following make rules:
---------------------------
service.def::  service-def.cpp $(ICONFIGFILES)
 $(RM) $@
 $(CPP)  -DLIBRARY_VERSION=1 <service-def.cpp | sed
-e '/^#  *[0-9][0-9]*  *.*$$/d' -e\ '/^XCOMM$$/s//#/' -e '/^XCOMM[^a-zA-Z0-9_]/s/^XCOMM/#/'
>$@
clean::
 $(RM) service.def
junk.c:
 echo "#include <cygwin/cygwin_dll.h>"  >junk.c
 echo "DECLARE_CYGWIN_DLL(dll_main);"  >>junk.c
 echo "int WINAPI dll_main(HANDLE a, DWORD reason, void *q)"
>>junk.c
 echo "{ return 1; }"    >>junk.c
libservice.dll: $(OBJS) junk.o service.def
 $(RM) libservice.a
 $(RM) libservice.dll
 if [ -f $(BASE_COUNTER) ]; then true; \
 else echo 0x67000000 > $(BASE_COUNTER); fi
 dllwrap -s --def service.def --output-lib libservice.a -o
libservice.dll $(OBJS) junk.o $(REQUIREDLIBS) -image-base `cat $(BASE_COUNTER)`
 IMAGE_LENGTH=`objdump -x libservice.dll |awk '/SizeOfImage/
{print "0x"$$2}'`; \
 export IMAGE_LENGTH=`expr '(' \`printf %u $$IMAGE_LENGTH\`
/ 65536 + 1 ')' '*' 65536` ; \
 export IMAGE_BASE=`cat $(BASE_COUNTER)`; \
 printf 0x%x `expr \`printf %u $$IMAGE_BASE\` + $$IMAGE_LENGTH`
> $(BASE_COUNTER)
 $(_NULLCMD_)
----------------------------
The problem is that I don't have any service-def.cpp, and I don't know
the correct format for it.
When I write my own 'service.def' and exclude the 'service.def' rule
from the makefile, it fails with:
dlltool: unrecognized option `--exclude-symbol=_cygwin_dll_entry@12'
My dllwrap is version 0.2.4 and dlltool 2.9.4.
When I copy the 'dllwrap' line to the command line it runs without error
(surprisingly), but the nm says 'No symbols in "libservice.dll"'.
Has anyone been though this sort of thing before?