gdbsupport: rename source files to .cc

This patch renames the .c source files in gdbsupport to .cc.

In the gdb directory, there is an argument against renaming the source
files, which is that it makes using some git commands more difficult to
do archeology.  Some commands have some kind of "follow" option that
makes git try to follow renames, but it doesn't work in all situations.

Given that we have just moved the gdbsupport directory, that argument
doesn't hold for source files in that directory.  I therefore suggest
renaming them to .cc, so that they are automatically recognized as C++
by various tools and editors.

The original motivation behind this is that when building gdbsupport
with clang, I get:

      CC       agent.o
    clang: error: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Werror,-Wdeprecated]

In the gdb/ directory, we make clang happy by passing "-x c++".  We
could do this in gdbsupport too, but I think that renaming the files is
a better long-term solution.

gdbserver still does its own build of gdbsupport, so a few changes in
its Makefile are necessary.

gdbsupport/ChangeLog:

	* Makefile.am: Rename source files from .c to .cc.
	(CC, CFLAGS): Don't override.
	(AM_CFLAGS): Rename to ...
	(AM_CXXFLAGS): ... this.
	* Makefile.in: Re-generate.
	* %.c: Rename to %.cc.

gdbserver/ChangeLog:

	* Makefile.in: Rename gdbsupport source files from .c to .cc.

1 files changed, 85 insertions, 0 deletions

diff --git a/gdbsupport/gdb_wait.cc b/gdbsupport/gdb_wait.cc
new file mode 100644
index 0000000..3213994
--- /dev/null
+++ b/gdbsupport/gdb_wait.cc
@@ -0,0 +1,85 @@
+/* Support code for standard wait macros in gdb_wait.h.
+
+   Copyright (C) 2019 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+
+#include "gdb_wait.h"
+
+#ifdef __MINGW32__
+
+/* The underlying idea is that when a Windows program is terminated by
+   a fatal exception, its exit code is the value of that exception, as
+   defined by the various EXCEPTION_* symbols in the Windows API
+   headers.  We thus emulate WTERMSIG etc. by translating the fatal
+   exception codes to more-or-less equivalent Posix signals.
+
+   The translation below is not perfect, because a program could
+   legitimately exit normally with a status whose value happens to
+   have the high bits set, but that's extremely rare, to say the
+   least, and it is deemed such a negligibly small probability of
+   false positives is justified by the utility of reporting the
+   terminating signal in the "normal" cases.  */
+
+# include <signal.h>
+
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>		/* for EXCEPTION_* constants */
+
+struct xlate_status
+{
+  /* The exit status (actually, fatal exception code).  */
+  DWORD status;
+
+  /* The corresponding signal value.  */
+  int sig;
+};
+
+int
+windows_status_to_termsig (unsigned long status)
+{
+  static const xlate_status status_xlate_tbl[] =
+    {
+     {EXCEPTION_ACCESS_VIOLATION,	  SIGSEGV},
+     {EXCEPTION_IN_PAGE_ERROR,		  SIGSEGV},
+     {EXCEPTION_INVALID_HANDLE,		  SIGSEGV},
+     {EXCEPTION_ILLEGAL_INSTRUCTION,	  SIGILL},
+     {EXCEPTION_NONCONTINUABLE_EXCEPTION, SIGILL},
+     {EXCEPTION_ARRAY_BOUNDS_EXCEEDED,	  SIGSEGV},
+     {EXCEPTION_FLT_DENORMAL_OPERAND,	  SIGFPE},
+     {EXCEPTION_FLT_DIVIDE_BY_ZERO,	  SIGFPE},
+     {EXCEPTION_FLT_INEXACT_RESULT,	  SIGFPE},
+     {EXCEPTION_FLT_INVALID_OPERATION,	  SIGFPE},
+     {EXCEPTION_FLT_OVERFLOW,		  SIGFPE},
+     {EXCEPTION_FLT_STACK_CHECK,	  SIGFPE},
+     {EXCEPTION_FLT_UNDERFLOW,		  SIGFPE},
+     {EXCEPTION_INT_DIVIDE_BY_ZERO,	  SIGFPE},
+     {EXCEPTION_INT_OVERFLOW,		  SIGFPE},
+     {EXCEPTION_PRIV_INSTRUCTION,	  SIGILL},
+     {EXCEPTION_STACK_OVERFLOW,		  SIGSEGV},
+     {CONTROL_C_EXIT,			  SIGTERM}
+    };
+
+  for (const xlate_status &x : status_xlate_tbl)
+    if (x.status == status)
+      return x.sig;
+
+  return -1;
+}
+
+#endif	/* __MINGW32__ */