gdb: guard <mutex> include with CXX_STD_THREAD

Change-Id: I4335fbfdabe49778fe37b08689eec59be94c424b

diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h
index b8c3a968dde8fb1aab79e3f1c3e893ec25e011da..f895b424efb4bf670b66196b358edb1ea33d566e 100644 (file)
--- a/gdb/dwarf2/read.h
+++ b/gdb/dwarf2/read.h
@@ -20,7 +20,9 @@
 #ifndef GDB_DWARF2_READ_H
 #define GDB_DWARF2_READ_H
 
+#if CXX_STD_THREAD
 #include <mutex>
+#endif
 #include <queue>
 #include "dwarf2/abbrev.h"
 #include "dwarf2/unit-head.h"