This patch provides a CPP-style include facility for GNU make. Consider the following example:

--------------- foo/config/g++.rules ----------------
#
# compiling code using g++
#

#...
---------------------- end --------------------------


--------------- foo/config/cxx.rules ----------------
#
# compiling code using Compaq C++
#

#...
---------------         end          ----------------


--------------- foo/config/c++.rules ----------------
#
# include one of the compiler-specific .rules
#
ifeq($(CXX),g++)
  include g++.rules
else
  include cxx.rules
endif
------------------------ end ------------------------

------------------- foo/Makefile --------------------
include config/c++.rules

#...
----------------------- end -------------------------


This reasonable example would not work because vanilla gnu make does not look for included files in parent's make-file directory. In other words make won't be able to find g++.rules or cxx.rules. The proposed patch introduces new flavor or include facility with the name 'cinclude' and the following semantic:

(1) cinclud'ed file if searched in parent's make-file directory and in directories specified with -I option.

(2) if cinclud'ed file is not found make will not attempt to rebuild it but rather immediately exit with error.

Thus the cinclude mechanism resembles CPP-style include. The above example corrected using cinclude would look as follows:

--------------- foo/config/c++.rules ----------------
#
# include one of the compiler-specific .rules
#
ifeq($(CXX),g++)
  cinclude g++.rules
else
  cinclude cxx.rules
endif
------------------------ end ------------------------