[OpenMP] [OMPD] Convert the error to warning for enabling OMPD in non-Linux platform

[Vigneshbalu]

Summary

OMPD is enabled by default on Linux machines and disabled on others.
However, if explicitly enabled it throws an error and exit while configuring.

It is mentioned in Bug: https://bugs.llvm.org/show_bug.cgi?id=51121

This patch, instead of throwing error, disables OMPD support with a warning message, so configuration can continue.

[protze.joachim]

lgtm

openmp/runtime/CMakeLists.txt

 if (LIBOMP_HAVE_OMPT_SUPPORT AND ("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux"))
   set(OMPD_DEFAULT TRUE)
 endif()
 
 set(LIBOMP_OMPD_SUPPORT ${OMPD_DEFAULT} CACHE BOOL
   "OMPD-support?")
 
 if(LIBOMP_OMPD_SUPPORT AND ((NOT LIBOMP_OMPT_SUPPORT) OR (NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "Linux")))
-  libomp_error_say("OpenMP Debug Interface(OMPD) requested but not available in this implementation")
+  libomp_warning_say("OpenMP Debug Interface(OMPD) requested but not available in this implementation")
+  set(LIBOMP_OMPD_SUPPORT FALSE)
 endif()
 
 # Error check hwloc support after config-ix has run
 if(LIBOMP_USE_HWLOC AND (NOT LIBOMP_HAVE_HWLOC))
   libomp_error_say("Hwloc requested but not available")
 endif()
 
 # Hierarchical scheduling support