Check TBB version in tbb-backed effective target check

      * testsuite/lib/libstdc++.exp (check_effective_target_tbb-backend):
      Add check for Thread Building Blocks 2018 or later.

From-SVN: r271450

libstdc++-v3/ChangeLog

+2019-05-20  Thomas Rodgers  <trodgers@redhat.com>
+
+	* testsuite/lib/libstdc++.exp (check_effective_target_tbb-backend):
+	Add check for Thread Building Blocks 2018 or later.
+
 2019-05-20  Jonathan Wakely  <jwakely@redhat.com>
 
 	* testsuite/experimental/names.cc: Only include Networking TS headers

libstdc++-v3/testsuite/lib/libstdc++.exp

@@ -1581,25 +1581,29 @@ proc check_effective_target_random_device { } {
 
 # Return 1 if tbb parallel backend is available
 proc check_effective_target_tbb-backend { } {
-		global cxxflags
-
-		# Set up and preprocess a C++ test program that depends
-		# on tbb
-		set src tbb_backend[pid].cc
-
-		set f [open $src "w"]
-		puts $f "#include <tbb/tbb.h>"
-		close $f
-		set lines [v3_target_compile $src /dev/null preprocess ""]
-		file delete $src
-
-		if [string match "" $lines] {
-				# No error message, preprocessing succeeded.
-				verbose "check_v3_tbb-backend: `1'" 2
-				return 1
-		}
-		verbose "check_v3_tbb-backend: `0'" 2
-		return 0
+    global cxxflags
+
+    # Set up and preprocess a C++ test program that depends
+    # on tbb
+    set src tbb_backend[pid].cc
+
+    set f [open $src "w"]
+    puts $f "#include <tbb/tbb.h>"
+    puts $f "#if TBB_INTERFACE_VERSION < 10000"
+    puts $f "#  error Intel(R) Threading Building Blocks 2018 is required; older versions are not supported."
+    puts $f "#endif"
+    close $f
+    
+    set lines [v3_target_compile $src /dev/null preprocess ""]
+    file delete $src
+
+    if [string match "" $lines] {
+	# No error message, preprocessing succeeded.
+	verbose "check_v3_tbb-backend: `1'" 2
+	return 1
+    }
+    verbose "check_v3_tbb-backend: `0'" 2
+    return 0
 }
 
 set additional_prunes ""