Fix memory leak in python.c:do_start_initialization

When intializing Python the path to the python binary is build the
following way

progname = concat (ldirname (python_libdir), SLASH_STRING, "bin",
		   SLASH_STRING, "python", (char *) NULL);

This is problematic as both concat and ldirname allocate memory for the
string they return.  Thus the memory allocated by ldirname cannot be
accessed afterwards causing a memory leak.  Fix it by temporarily storing
libdir in a variable and xfree it after concat.

gdb/ChangeLog:
	python/python.c (do_start_initialization): Fix memory leak.

1 files changed, 3 insertions, 1 deletions

diff --git a/gdb/python/python.c b/gdb/python/python.c
index 73fb3d0295..d814252303 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -1550,8 +1550,10 @@ do_start_initialization ()
      /foo/bin/python
      /foo/lib/pythonX.Y/...
      This must be done before calling Py_Initialize.  */
-  progname = concat (ldirname (python_libdir), SLASH_STRING, "bin",
+  const char *libdir = ldirname (python_libdir);
+  progname = concat (libdir, SLASH_STRING, "bin",
 		     SLASH_STRING, "python", (char *) NULL);
+  xfree (libdir);
 #ifdef IS_PY3K
   oldloc = xstrdup (setlocale (LC_ALL, NULL));
   setlocale (LC_ALL, "");