sim/ppc/Makefile uses GNU Make specific features

[Chris January <chris.january@allinea.com>]

sim/ppc/Makefile uses GNU Make specific features but doesn't test for
GNU make in configure:

1. $< used in a non-default rule:

gentmap: ../common/gentmap.c
        $(CC_FOR_BUILD) $(BUILD_CFLAGS) -I. -I../common -I
$(srcdir)/../common -o gentmap $< $(BUILD_LIBS)

From the autoconf manual:

"Posix says that the ‘$<’ construct in makefiles can be used only in
inference rules and in the ‘.DEFAULT’ rule; its meaning in ordinary
rules is unspecified. Solaris make for instance replaces it with the
empty string. OpenBSD (3.0 and later) make diagnoses these uses and
errors out. "

Result (on AIX, with AIX make):

        gcc -g -O2 -I. -I. -I./../../include -I../../bfd -I./../../bfd
-I../../gdb -I./../../gdb  -I./../../gdb/config  -I. -I../common
-I./../common -o gentmap  
gcc: no input files
make: 1254-004 The error code from the last command is 1.

2. psim depends on -lz, which is not a real file:

LIBS = -lz

psim: $(TARGETLIB) main.o $(LIBIBERTY_LIB) $(BFD_LIB) $(LIBS)
$(LIBINTL_DEP)

Result (again, with AIX make):

make: 1254-002 Cannot find a rule to create target -lz from
dependencies.
Stop.

Chris