[build] - Support for removing OPENMP_STANDALONE_BUILD logic upstream

Support for openmp and offload debug/perf/asan libraries has moved to
build_llvm_runtimes_standalone.sh. This script invokes the cmake in
llvm-project/runtimes instead of the openmp or offload directories.
Upstream will eventually remove OPENMP_STANDALONE_BUILD.

- LLVM_BINARY_DIR introduced to notify the runtimes standalone build where clang is.
- USE_LIBOMPTARGET_LIBRARY_DIR=On introduced to keep offload build files
out of the install directory.

Author: estewart08

bin/build_aomp.sh

@@ -98,7 +98,7 @@ echo
 components="$AOMP_COMPONENT_LIST"
 
 if [ "$AOMP_STANDALONE_BUILD" == 1 ] ; then
-  components="$components rocprofiler-register rocr openmp offload extras comgr rocminfo rocm_smi_lib amdsmi"
+  components="$components rocprofiler-register rocr llvm_runtimes_standalone extras comgr rocminfo rocm_smi_lib amdsmi"
   _hostarch=$(uname -m)
   # The rocclr architecture is very x86 centric so it will not build on ppc64. Without
   # rocclr, we have no HIP or OpenCL for ppc64 :-( However, rocr works for ppc64 so AOMP works.
@@ -132,10 +132,7 @@ else
   # libdevice, project, comgr, rocminfo, hipamd, rocdbgapi, rocgdb,
   # roctracer, rocprofiler, rocm_smi_lib, and amdsmi should be found
   # in ROCM in /opt/rocm.  The ROCM build only needs these components:
-  components="extras openmp"
-  if [ -f "$AOMP_REPOS/$AOMP_PROJECT_REPO_NAME/offload/CMakeLists.txt" ]; then
-    components="$components offload"
-  fi
+  components="llvm_runtimes_standalone"
   if [ "$AOMP_SKIP_FLANG" == 0 ] ; then
     if [ "$SANITIZER" == 1 ] && [ -f "$AOMP/bin/flang-classic" ] ; then
       components="$components pgmath flang flang_runtime"