a few DBG=-g build fixes, both arches

- setlogin() not available
	- softfloat needed in -lminc for arm
	- libminc: we have to set LIBCDIR for the included files,
	  so use that instead of LIBCSRCDIR

Change-Id: I7f92621ebbca9ce08dc377b3fa61dee089071757

lib/libminc/arch/i386/Makefile.libc.inc

@@ -4,12 +4,12 @@ SRCS+=  memchr.S memcmp.S memcpy.S memmove.S memset.S \
 	strncmp.S strrchr.S
 
 .for i in infinityl.c
-.PATH.c: ${LIBCSRCDIR}/arch/${MACHINE_ARCH}/gen
+.PATH.c: ${LIBCDIR}/arch/${MACHINE_ARCH}/gen
 SRCS+= ${i}
 .endfor
 # Import from string
 .for i in bcmp.S
-.PATH.S: ${LIBCSRCDIR}/arch/${MACHINE_ARCH}/string
+.PATH.S: ${LIBCDIR}/arch/${MACHINE_ARCH}/string
 SRCS+= ${i}
 CPPFLAGS.${i}+= -D_LIBC
 .endfor