Detect runtime build of the OpenMP runtime

Inspired by #88914

Author: mjklemm

flang/test/lit.site.cfg.py.in

@@ -25,7 +25,11 @@ config.cc = "@CMAKE_C_COMPILER@"
 config.osx_sysroot = path(r"@CMAKE_OSX_SYSROOT@")
 config.targets_to_build = "@TARGETS_TO_BUILD@"
 config.default_sysroot = "@DEFAULT_SYSROOT@"
-config.have_openmp_rtl = ("@LLVM_TOOL_OPENMP_BUILD@" == "TRUE")
+config.have_openmp_rtl = ("@LLVM_TOOL_OPENMP_BUILD@" == "TRUE") or ("openmp" in "@LLVM_ENABLE_RUNTIMES@".lower().split(";"))
+if "openmp" in "@LLVM_ENABLE_RUNTIMES@".lower().split(";"):
+    config.openmp_module_dir = "@CMAKE_BINARY_DIR@/runtimes/runtimes-bins/openmp/runtime/src"
+else:
+    config.openmp_module_dir = None
 config.flang_runtime_f128_math_lib = "@FLANG_RUNTIME_F128_MATH_LIB@"
 
 import lit.llvm