[ADMB Users] precompiled headers

[dave fournier]

I did not do any timings but this appears to be all
that is needed to use admodel.h as a precompiled header in nh99


these are additions to the makefile in subdir nh99

.SUFFIXES: .h.gch .h

# add -H to compile
%.obj: %.cpp
         $(CXX) $(CXXFLAGS) -H $< -o $(LIBPATH)/$*.obj
# build precompiled header
%.h.gch: %.h
         $(CXX) $(CXXFLAGS) -x c++-header   $<



add admodel.h to top of objects.lst