Include thrid-party library headers with < > instead of " "

Found by Cppcheck (missingInclude).

Include thrid-party library headers with < > instead of " "
540c1d8c · Christoph Grüninger · 206e2b76 · 540c1d8c
Commit 540c1d8c authored 9 months ago by Christoph Grüninger
--- a/dune/istl/ldl.hh
+++ b/dune/istl/ldl.hh
@@ -14,8 +14,8 @@
 #ifdef __cplusplus
 extern "C"
 {
-#include "ldl.h"
-#include "amd.h"
+#include <ldl.h>
+#include <amd.h>
 }
 #endif