CMake 3.15+ Updates, master branch (2020.01.09.)

This is a sibling of atlasexternals!595 (merged). It only works with the code proposed in that MR. (Hence it's a WIP, as it wouldn't work as-is. I have additional changes locally, which make sure that my test build uses https://gitlab.cern.ch/akraszna/atlasexternals/tree/CMakeUpdates-master-20200106.

As described in atlasexternals!595 (merged) and in ATLINFR-3157, we need to make some changes to be compatible with CMake 3.15+. These are the proposed changes.

The most important change is that atlas_project(...) no longer receives the name and version of a project. Those now have to be specified in a call to project(...) at the top of the project CMakeLists.txt files. However the version numbers, in practice, are still read in from the same version.txt files as before. So for people not regularly editing the project CMakeLists.txt files, this should not cause any difference.

Most of the documentation / discussion about these updates is in atlasexternals!595 (merged).

Tagging @fwinkl, @tsulaia, @ssnyder and @wlampl.

Build/AtlasBuildScripts/build_Gaudi.sh

 #!/bin/bash
 #
+# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+#
 # Script used for building Gaudi.
 #
 
@@ -14,7 +16,8 @@ set -o pipefail
 usage() {
     echo "Usage: build_Gaudi.sh <-s source dir> <-b build dir> " \
         "<-i install dir> <-e externals dir> <-p externals project name> " \
-        "<-f platform name> [-r RPM dir] [-t build type] [-x extra CMake arguments]"
+        "<-f platform name> [-r RPM dir] [-t build type] [-v version] " \
+        "[-x extra CMake arguments]"
 }
 
 # Parse the command line arguments:
@@ -26,8 +29,9 @@ EXTPROJECT=""
 PLATFORM=""
 RPMDIR=""
 BUILDTYPE="Release"
+PROJECTVERSION=""
 EXTRACMAKE=()
-while getopts ":s:b:i:e:p:f:r:t:x:h" opt; do
+while getopts ":s:b:i:e:p:f:r:t:x:v:h" opt; do
     case $opt in
         s)
             SOURCEDIR=$OPTARG
@@ -56,6 +60,9 @@ while getopts ":s:b:i:e:p:f:r:t:x:h" opt; do
         x)
             EXTRACMAKE+=($OPTARG)
             ;;
+        v)
+            PROJECTVERSION=$OPTARG
+            ;;
         h)
             usage
             exit 0
@@ -76,7 +83,7 @@ done
 # Make sure that the required options were all specified:
 if [ "$SOURCEDIR" = "" ] || [ "$BUILDDIR" = "" ] || [ "$INSTALLDIR" = "" ] \
     || [ "$EXTDIR" = "" ] || [ "$EXTPROJECT" = "" ] \
-    || [ "$PLATFORM" = "" ]; then
+    || [ "$PLATFORM" = "" ] || [ "$PROJECTVERSION" = "" ]; then
     echo "Not all required parameters received!"
     usage
     exit 1
@@ -89,8 +96,6 @@ cd ${BUILDDIR} || ((ERROR_COUNT++))
 # Set up the externals project:
 source ${EXTDIR}/setup.sh || ((ERROR_COUNT++))
 
-#FIXME: simplify error counting below while keeping '| tee ...'
-
 # Configure the build:
 error_stamp=`mktemp .tmp.error.XXXXX` ; rm -f $error_stamp
 {
@@ -98,8 +103,8 @@ rm -f CMakeCache.txt
 rm -rf * # Remove the full build temporarily, to fix GAUDI-1315
 cmake -DCMAKE_BUILD_TYPE:STRING=${BUILDTYPE} -DCTEST_USE_LAUNCHERS:BOOL=TRUE \
     -DGAUDI_ATLAS:BOOL=TRUE -DGAUDI_ATLAS_BASE_PROJECT:STRING=${EXTPROJECT} \
-    -DCMAKE_INSTALL_PREFIX:PATH=/InstallArea/${PLATFORM} ${EXTRACMAKE[@]} \
-    ${SOURCEDIR} || touch $error_stamp
+    -DCMAKE_INSTALL_PREFIX:PATH=/GAUDI/${PROJECTVERSION}/InstallArea/${PLATFORM} \
+    ${EXTRACMAKE[@]} ${SOURCEDIR} || touch $error_stamp
 } 2>&1 | tee cmake_config.log 
 test -f $error_stamp && ((ERROR_COUNT++))
 rm -f $error_stamp