debug/gdb: install dependable libs in a generic target static libs dir

For now, ncurses is the only dependable target library built for gdb.
But expat is coming, and there's no reason to install each library in
its own place.

So, install ncurses in a generic directory, where other dependable
libraries can be installed as well.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

--- glibc-2_9.orig/nptl/init.c	2007-10-15 22:25:25.000000000 +0200

+++ glibc-2_9/nptl/init.c	2010-08-18 10:46:06.109098646 +0200

@@ -236,7 +236,7 @@

 /* This can be set by the debugger before initialization is complete.  */

-static bool __nptl_initial_report_events;

+static bool __nptl_initial_report_events __attribute_used__;

 void

 __pthread_initialize_minimal_internal (void)