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, 95 insertions, 0 deletions

diff --git a/gdbsupport/gdb_tilde_expand.cc b/gdbsupport/gdb_tilde_expand.cc
new file mode 100644
index 00000000000..6671629a17e
--- /dev/null
+++ b/gdbsupport/gdb_tilde_expand.cc
@@ -0,0 +1,95 @@
+/* Perform tilde expansion on paths for GDB and gdbserver.
+
+   Copyright (C) 2017-2020 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_tilde_expand.h"
+#include <glob.h>
+
+/* RAII-style class wrapping "glob".  */
+
+class gdb_glob
+{
+public:
+  /* Construct a "gdb_glob" object by calling "glob" with the provided
+     parameters.  This function can throw if "glob" fails.  */
+  gdb_glob (const char *pattern, int flags,
+	    int (*errfunc) (const char *epath, int eerrno))
+  {
+    int ret = glob (pattern, flags, errfunc, &m_glob);
+
+    if (ret != 0)
+      {
+	if (ret == GLOB_NOMATCH)
+	  error (_("Could not find a match for '%s'."), pattern);
+	else
+	  error (_("glob could not process pattern '%s'."),
+		 pattern);
+      }
+  }
+
+  /* Destroy the object and free M_GLOB.  */
+  ~gdb_glob ()
+  {
+    globfree (&m_glob);
+  }
+
+  /* Return the GL_PATHC component of M_GLOB.  */
+  int pathc () const
+  {
+    return m_glob.gl_pathc;
+  }
+
+  /* Return the GL_PATHV component of M_GLOB.  */
+  char **pathv () const
+  {
+    return m_glob.gl_pathv;
+  }
+
+private:
+  /* The actual glob object we're dealing with.  */
+  glob_t m_glob;
+};
+
+/* See gdbsupport/gdb_tilde_expand.h.  */
+
+std::string
+gdb_tilde_expand (const char *dir)
+{
+  gdb_glob glob (dir, GLOB_TILDE_CHECK, NULL);
+
+  gdb_assert (glob.pathc () > 0);
+  /* "glob" may return more than one match to the path provided by the
+     user, but we are only interested in the first match.  */
+  std::string expanded_dir = glob.pathv ()[0];
+
+  return expanded_dir;
+}
+
+/* See gdbsupport/gdb_tilde_expand.h.  */
+
+gdb::unique_xmalloc_ptr<char>
+gdb_tilde_expand_up (const char *dir)
+{
+  gdb_glob glob (dir, GLOB_TILDE_CHECK, NULL);
+
+  gdb_assert (glob.pathc () > 0);
+  /* "glob" may return more than one match to the path provided by the
+     user, but we are only interested in the first match.  */
+  return make_unique_xstrdup (glob.pathv ()[0]);
+}