Workaround double free problems

The source code for handling images has a double free problem. Recent versions
of the GNU libc have a mechanism to automagically abort the program in such a
case. This causes Mosaic to crash if images are displayed.

I work around this issue by turning of automatical program abortion with a call
to mallopt().

src/main.c

@@ -71,6 +71,7 @@
 #include <signal.h>
 #include <sys/utsname.h>
 #include <string.h>
+#include <malloc.h>
 
 /* swp */
 #define _KCMS_H_
@@ -231,6 +232,14 @@ main (int argc, char **argv, char **envp)
   /* Since we're doing lots of TCP, just ignore SIGPIPE altogether. */
   signal (SIGPIPE, SIG_IGN);
 
+#ifdef M_CHECK_ACTION
+  /* some code here has the habit of freeing pointers twice. The glibc
+     catches this and causes the program to abort. In order to make the
+     code somehow work, we turn aborting the program off. */
+
+  mallopt(M_CHECK_ACTION,5);
+#endif
+
   InitChildProcessor();
   MoCCIPreInitialize();