config: add an option not to remove the destination directory

In certain circumstances, removing the destination/installation directory
is a bad idea. For example, when the build environment is already taking
care of sanitising the build tree, and pre-installs stuff in there, it is
a very bad idea to remove the destination directory.

This happens now in buildroot, as the crostool-NG backend now installs the
toolchain in the common host-tools directory, and pre-install there a few
host-utilities (eg. host-automake and host-gawk).

Provide a config knob to turn on/off the removal of the destination
directory, defaulting to 'y' (previous behavior), and forced to 'n' when
used as a backend.

Reported-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

diff -dur strace-4.5.16.orig/syscall.c strace-4.5.16/syscall.c

--- strace-4.5.16.orig/syscall.c	2006-12-21 23:13:33.000000000 +0100

+++ strace-4.5.16/syscall.c	2007-07-14 19:21:44.000000000 +0200

@@ -1045,6 +1045,15 @@

 		/*

 		 * Note: we only deal with only 32-bit CPUs here.

 		 */

+

+		if (!(tcp->flags & TCB_INSYSCALL) &&

+		    (tcp->flags & TCB_WAITEXECVE)) {

+			/* caught a fake syscall from the execve's exit */

+			tcp->flags &= ~TCB_WAITEXECVE;

+			return 0;

+		}

+

+

 		if (regs.ARM_cpsr & 0x20) {

 			/*

 			 * Get the Thumb-mode system call number