libgomp C++ testsuite: Use 'lang_include_flags' instead of 'libstdcxx_includes'

With nvptx offloading configured, and supported, and CUDA available:

    $ make check-target-libgomp RUNTESTFLAGS="--all c.exp=context-1.c c++.exp=context-1.c"
    [...]
    Running [...]/libgomp.oacc-c/c.exp ...
    PASS: libgomp.oacc-c/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O0  (test for excess errors)
    PASS: libgomp.oacc-c/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O0  execution test
    PASS: libgomp.oacc-c/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O2  (test for excess errors)
    PASS: libgomp.oacc-c/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O2  execution test
    UNSUPPORTED: libgomp.oacc-c/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_host=1 -DACC_MEM_SHARED=1 -foffload=disable  -O2
    Running [...]/libgomp.oacc-c++/c++.exp ...
    PASS: libgomp.oacc-c++/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O0  (test for excess errors)
    PASS: libgomp.oacc-c++/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O0  execution test
    PASS: libgomp.oacc-c++/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O2  (test for excess errors)
    PASS: libgomp.oacc-c++/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O2  execution test
    UNSUPPORTED: libgomp.oacc-c++/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_host=1 -DACC_MEM_SHARED=1 -foffload=disable  -O2
    [...]

..., but for 'c++.exp=context-1.c' alone, we currently get all-UNSUPPORTED:

    $ make check-target-libgomp RUNTESTFLAGS_="--all c++.exp=context-1.c"
    [...]
    Running [...]/libgomp.oacc-c++/c++.exp ...
    UNSUPPORTED: libgomp.oacc-c++/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O0
    UNSUPPORTED: libgomp.oacc-c++/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O2
    UNSUPPORTED: libgomp.oacc-c++/../libgomp.oacc-c-c++-common/context-1.c -DACC_DEVICE_TYPE_host=1 -DACC_MEM_SHARED=1 -foffload=disable  -O2
    [...]

That is, if 'c.exp' executes first, it does successfully evaluate
'dg-require-effective-target openacc_cublas' -- and does cache this result (so
it isn't reevaluated for 'c++.exp').  However, for 'c++.exp' alone (that is,
without the 'c.exp' result cached), we run into:

    spawn -ignore SIGHUP [xgcc] [...] -x c++ openacc_cublas2311907.c [...]
    In file included from /usr/include/cuda_fp16.h:3673,
                     from /usr/include/cublas_api.h:75,
                     from /usr/include/cublas_v2.h:65,
                     from openacc_cublas2311907.c:3:
    /usr/include/cuda_fp16.hpp:67:10: fatal error: utility: No such file or directory

We're missing include paths to C++/libstdc++ build-tree headers.

Fix this by using the mechanism introduced for Fortran in
r212268 (commit f707da16f714f7fe5a42391748212c84dfec639b) re
"libgomp.fortran/fortran.exp - add -fintrinsic-modules-path ${blddir}".

	libgomp/
	* testsuite/libgomp.c++/c++.exp: Use 'lang_include_flags' instead
	of 'libstdcxx_includes'.
	* testsuite/libgomp.oacc-c++/c++.exp: Likewise.

2 files changed, 6 insertions, 8 deletions

diff --git a/libgomp/testsuite/libgomp.c++/c++.exp b/libgomp/testsuite/libgomp.c++/c++.exp
index f4884e2..5b9a592 100644
--- a/libgomp/testsuite/libgomp.c++/c++.exp
+++ b/libgomp/testsuite/libgomp.c++/c++.exp
@@ -66,13 +66,12 @@ if { $lang_test_file_found } {
 
     set flags_file "${blddir}/../libstdc++-v3/scripts/testsuite_flags"
     if { [file exists $flags_file] } {
-	set libstdcxx_includes [exec sh $flags_file --build-includes]
-    } else {
-	set libstdcxx_includes ""
+	set lang_source_re {^.*\.[cC]$}
+	set lang_include_flags [exec sh $flags_file --build-includes]
     }
 
     # Main loop.
-    dg-runtest $tests "" "$libstdcxx_includes $DEFAULT_CFLAGS"
+    dg-runtest $tests "" $DEFAULT_CFLAGS
 }
 
 # See above.
diff --git a/libgomp/testsuite/libgomp.oacc-c++/c++.exp b/libgomp/testsuite/libgomp.oacc-c++/c++.exp
index 42e0395..0b235ba 100644
--- a/libgomp/testsuite/libgomp.oacc-c++/c++.exp
+++ b/libgomp/testsuite/libgomp.oacc-c++/c++.exp
@@ -72,9 +72,8 @@ if { $lang_test_file_found } {
 
     set flags_file "${blddir}/../libstdc++-v3/scripts/testsuite_flags"
     if { [file exists $flags_file] } {
-	set libstdcxx_includes [exec sh $flags_file --build-includes]
-    } else {
-	set libstdcxx_includes ""
+	set lang_source_re {^.*\.[cC]$}
+	set lang_include_flags [exec sh $flags_file --build-includes]
     }
 
     # Test with all available offload targets, and with offloading disabled.
@@ -147,7 +146,7 @@ if { $lang_test_file_found } {
 	    }
 	}
 
-	gcc-dg-runtest $tests "$tagopt" "$libstdcxx_includes"
+	gcc-dg-runtest $tests "$tagopt" ""
     }
     unset offload_target
 } else {