[gcc r16-6178] testsuite: require dot for diagnostic-test-graphs-html.c [PR123142]

[David Malcolm]

https://gcc.gnu.org/g:e50ec079f5f356f14e156230d9d4c0bbe081fb17

commit r16-6178-ge50ec079f5f356f14e156230d9d4c0bbe081fb17
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Tue Dec 16 16:11:50 2025 -0500

    testsuite: require dot for diagnostic-test-graphs-html.c [PR123142]
    
    gcc/testsuite/ChangeLog:
            PR diagnostics/123142
            * gcc.dg/plugin/diagnostic-test-graphs-html.c: Add
            dg-require-dot directive.
    
    Signed-off-by: David Malcolm <dmalcolm@redhat.com>

Diff:
---
 gcc/testsuite/gcc.dg/plugin/diagnostic-test-graphs-html.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-graphs-html.c b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-graphs-html.c
index 2256a63465f1..9af0894310d3 100644
--- a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-graphs-html.c
+++ b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-graphs-html.c
@@ -1,6 +1,6 @@
 /* { dg-do compile } */
 /* { dg-options "-fdiagnostics-add-output=experimental-html:javascript=no" } */
-
+/* { dg-require-dot "" } */
 extern void here (void);
 
 void test_graphs (void)