debug/ltrace: fix building for mips

ltrace 0.5.3 currently fails to build for target mips because MY_TARGET
(introduced by patches/ltrace/0.5.3/150-allow-configurable-arch.patch)
is set to 'mips' via CT_ARCH, while the mips specific stuff in ltrace
(0.5.3) is stored under sysdeps/linux-gnu/mipsel:

result: *** No rule to make target `mips/arch.h', needed by `sysdep.h'.
Stop.

The following patch fixes this issue

Signed-off-by: "Horst Kronstorfer" <horst.kronstorfer@aon.at>
[yann.morin.1998@anciens.enib.fr: reformat commit log]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
(transplanted from 2115901c7f07181d92ddbd7dd7ebeaa72e4fb176)

 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