XL: Fix compatibility with newer clang-based XL on Linux

CMakeLists.txt

@@ -1039,8 +1039,12 @@ IF(KWSYS_STANDALONE OR CMake_SOURCE_DIR)
     # Some Apple compilers produce bad optimizations in this source.
     IF(APPLE AND CMAKE_C_COMPILER_ID MATCHES "^(GNU|LLVM)$")
       SET_SOURCE_FILES_PROPERTIES(testProcess.c PROPERTIES COMPILE_FLAGS -O0)
-    ELSEIF(CMAKE_C_COMPILER_ID STREQUAL "XL")
+    ELSEIF(CMAKE_C_COMPILER_ID STREQUAL "XL" AND
+           NOT (CMAKE_SYSTEM MATCHES "Linux.*ppc64le" AND
+                NOT CMAKE_C_COMPILER_VERSION VERSION_LESS "13.1.1"))
       # Tell IBM XL not to warn about our test infinite loop
+      # v13.1.1 and newer on Linux ppc64le is clang based and does not accept
+      # the -qsuppress option
       SET_PROPERTY(SOURCE testProcess.c PROPERTY COMPILE_FLAGS -qsuppress=1500-010)
     ENDIF()