build_oai: add --build-tool-opt to pass options to build tool

There are command line options that one might pass to ninja/make, but
for which cmake does not provide an interface. For instance, make/ninja
support -k/-kN to "keep going" after errors. Cmake does not provide an
option, but it is still possible to pass this. Make a build_oai option
to allow this, used in the next commit.

cmake_targets/tools/build_helper

@@ -208,20 +208,20 @@ check_errors() {
 }
 
 compilations() {
-  [[ $# -gt 2 ]] || echo_fatal "compilations needs more than three arguments"
+  [[ $# -eq 4 ]] || echo_fatal "compilations <dir> <logfile> <targets> <build-tool-opt>"
   local dir=$1
-  shift 1
-  local logfile=$1
-  shift 1
-  local targets=$@
+  local logfile=$2
+  local targets=$3
+  local build_tool_opt=$4
   local verbose=$([ "$VERBOSE_COMPILE" == "1" ] && echo "-v" || echo "")
   echo cd $OPENAIR_DIR/cmake_targets/$dir/build
   cd $OPENAIR_DIR/cmake_targets/$dir/build
-  echo_info "Running \"$CMAKE --build . $verbose --target $targets -- -j$(nproc)\"" $green
+  cmd="$CMAKE --build . ${verbose} --target ${targets} -- ${build_tool_opt}"
+  echo_info "Running \"${cmd}\"" $green
   echo "Log file for compilation is being written to: $dlog/$logfile"
   set +e
   {
-    $CMAKE --build . $verbose --target $targets -- -j$(nproc)
+    eval ${cmd}
     ret=$?
   } > $dlog/$logfile 2>&1
   # Print the errors and warnings for CI purposes