Remove GNUmakefile, document cmake building.

The README now suggests using nice and make -j for multicore machines.

CMakeLists.txt

@@ -274,9 +274,3 @@ configure_la (${project} ${${project}_TARGET} ${project}_LIBTOOL_ARCHIVE)
 ### clean in-source builds ###
 include (OpmDistClean)
 opm_dist_clean (${project})
-
-# smart wrapper that auto-parallelizes builds
-file (COPY
-	GNUmakefile
-	DESTINATION ${PROJECT_BINARY_DIR}
-	)

GNUmakefile

@@ -1,43 +0,0 @@
-# GNUmakefile is processed before Makefile, which is why we arrive here
-# first; when we call the other makefile, then we must specify its real
-# name with the -f parameter
-
-# figure out the number of processors from the system, add one and round
-# to nearest integer. this is the maximum number of processes we want running
-# at the same time (one for each core and one stuck on I/O)
-# if we are running this is a VM, then /proc won't be mounted and we revert
-# to single CPU processing
-CPUINFO:=/proc/cpuinfo
-NUM_CPUS:=$(shell test -r $(CPUINFO) && grep -P -c '^processor\t:' $(CPUINFO) || echo 0)
-PROCS:=$(shell echo "("$(NUM_CPUS)+1")"/1 | bc)
-
-# use these utilities if they are available
-IONICE:=$(shell test -x "$$(which ionice)" && echo ionice -c2 -n7)
-NICE:=$(shell test -x "$$(which nice)" && echo nice)
-
-# we do dependency management the right way; don't attempt to cache
-export CCACHE_DISABLE:=1
-
-# ignore that there may be files with these names, we are going to call
-# the other make regardless
-.PHONY: __everything $(MAKECMDGOALS)
-
-# outsource the processing to the real makefile, running in parallel and
-# in a nice environment so that it doesn't hog our workstation. if there
-# is nothing else happening on the box, then it will run just as fast
-# the leading plus makes us run this regardless of options, see
-# http://www.gnu.org/software/make/manual/make.html#Instead-of-Execution
-__everything:
-# only put on a parallel flag if there isn't already one; otherwise we
-# get the warning "-jN forced in submake: disabling jobserver mode".
-# this have to happen inside the rule, because -j option is removed from
-# MAKEFLAGS outside
-	+@$(IONICE) $(NICE) $(MAKE) --no-print-directory -f Makefile $(if $(findstring -j,$(MAKEFLAGS)),,-j $(PROCS)) $(MAKECMDGOALS)
-
-# automatically generate all the goals we are asked to make and delegate
-# processing of them to the real makefile through the dependency (since
-# everything depends on the same thing, then we only call the other make
-# once). the dummy command is just there to make sure that make doesn't
-# show the "Nothing to do for `foo'" message after processing
-$(MAKECMDGOALS): __everything
-	@true

README

@@ -118,10 +118,20 @@ BUILDING
 There are two ways to build the opm-core library:
 
 1. As a stand-alone library.
- cd opm-core
- ./configure
+Assuming you are standing in the directory containing your checked out
+clone of opm-core, issue the commands
+
+ mkdir opm-core-build
+ cd opm-core-build
+ cmake ../opm-core
  make
 
+If you have a multi-core computer you may want to do a parallel
+build. To do so, replace the make command with:
+
+ nice make -j 2
+
+This will start a parallel build appropriate for a two-core system.
 If you want to install the library:
 
  sudo make install