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, 118 insertions, 0 deletions

diff --git a/gdbsupport/gdb-dlfcn.cc b/gdbsupport/gdb-dlfcn.cc
new file mode 100644
index 0000000..1a755bd
--- /dev/null
+++ b/gdbsupport/gdb-dlfcn.cc
@@ -0,0 +1,118 @@
+/* Platform independent shared object routines for GDB.
+
+   Copyright (C) 2011-2020 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-dlfcn.h"
+
+#ifdef HAVE_DLFCN_H
+#include <dlfcn.h>
+#elif __MINGW32__
+#include <windows.h>
+#else
+/* Unsupported configuration. */
+#define NO_SHARED_LIB
+#endif
+
+#ifdef NO_SHARED_LIB
+
+gdb_dlhandle_up
+gdb_dlopen (const char *filename)
+{
+  gdb_assert_not_reached ("gdb_dlopen should not be called on this platform.");
+}
+
+void *
+gdb_dlsym (const gdb_dlhandle_up &handle, const char *symbol)
+{
+  gdb_assert_not_reached ("gdb_dlsym should not be called on this platform.");
+}
+
+void
+dlclose_deleter::operator() (void *handle) const
+{
+  gdb_assert_not_reached ("gdb_dlclose should not be called on this platform.");
+}
+
+int
+is_dl_available (void)
+{
+  return 0;
+}
+
+#else /* NO_SHARED_LIB */
+
+gdb_dlhandle_up
+gdb_dlopen (const char *filename)
+{
+  void *result;
+#ifdef HAVE_DLFCN_H
+  result = dlopen (filename, RTLD_NOW);
+#elif __MINGW32__
+  result = (void *) LoadLibrary (filename);
+#endif
+  if (result != NULL)
+    return gdb_dlhandle_up (result);
+
+#ifdef HAVE_DLFCN_H
+  error (_("Could not load %s: %s"), filename, dlerror());
+#else
+  {
+    LPVOID buffer;
+    DWORD dw;
+
+    dw = GetLastError();
+
+    FormatMessage (FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+                   FORMAT_MESSAGE_IGNORE_INSERTS,
+                   NULL, dw, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                   (LPTSTR) &buffer,
+                   0, NULL);
+
+    error (_("Could not load %s: %s"), filename, (char *) buffer);
+  }
+#endif
+}
+
+void *
+gdb_dlsym (const gdb_dlhandle_up &handle, const char *symbol)
+{
+#ifdef HAVE_DLFCN_H
+  return dlsym (handle.get (), symbol);
+#elif __MINGW32__
+  return (void *) GetProcAddress ((HMODULE) handle.get (), symbol);
+#endif
+}
+
+void
+dlclose_deleter::operator() (void *handle) const
+{
+#ifdef HAVE_DLFCN_H
+  dlclose (handle);
+#elif __MINGW32__
+  FreeLibrary ((HMODULE) handle);
+#endif
+}
+
+int
+is_dl_available (void)
+{
+  return 1;
+}
+
+#endif /* NO_SHARED_LIB */