* configure checks for /usr/bin/arch to determine whether "arch" is ok
  to use, so don't rely on the path at runtime, since GNU arch doesn't
  understand -arch at all (and only returns the current arch name)

--- src/gdb/fork-child.c
+++ src/gdb/fork-child.c
@@ -243,7 +243,7 @@
 	  arch_string = "x86_64";
 #endif
 	if (arch_string != NULL)
-	  sprintf (shell_command, "%s exec arch -arch %s ", shell_command, arch_string);
+	  sprintf (shell_command, "%s exec /usr/bin/arch -arch %s ", shell_command, arch_string);
 	else
 	  strcat (shell_command, "exec ");
       }