gdb: include <mutex> in dwarf2/read.h

The buildbot pointed out this compilation failure on AlmaLinux, with g++
8.5.0, which is not seen on more recent systems:

     CXX    gdbtypes.o
    In file included from ../../binutils-gdb/gdb/gdbtypes.c:39:
    ../../binutils-gdb/gdb/dwarf2/read.h:639:8: error: ‘mutex’ in namespace ‘std’ does not name a type
       std::mutex dwo_files_lock;
            ^~~~~
    ../../binutils-gdb/gdb/dwarf2/read.h:639:3: note: ‘std::mutex’ is defined in header ‘<mutex>’; did you forget to ‘#include <mutex>’?
    ../../binutils-gdb/gdb/dwarf2/read.h:35:1:
    +#include <mutex>

    ../../binutils-gdb/gdb/dwarf2/read.h:639:3:
       std::mutex dwo_files_lock;
       ^~~

Fix it by including <mutex> in dwarf2/read.h.

Change-Id: Iba334a3dad217c86841a5e804d0f386876f5ff2f

diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h
index e676d64f2e981bcbaec2bdc933fa84fdd0d5b7ef..b8c3a968dde8fb1aab79e3f1c3e893ec25e011da 100644 (file)
--- a/gdb/dwarf2/read.h
+++ b/gdb/dwarf2/read.h
@@ -20,6 +20,7 @@
 #ifndef GDB_DWARF2_READ_H
 #define GDB_DWARF2_READ_H
 
+#include <mutex>
 #include <queue>
 #include "dwarf2/abbrev.h"
 #include "dwarf2/unit-head.h"