Change logic for "what is cross toolchain"

Try to detect a cross-compiler based on if $CC contains "-".  Notably,
"cc" might still be a cross-compiler in the strictest sense of the
word if we're e.g. building rumprun.  Here, the driving logic is to
make locating the rest of the toolchain easy without the user having
specify everything.  For example, if CC=cc is given, then it's a good
bet that NM=nm.  Likewise, if CC=foo-bar-cc is given, then it's a good
bet that NM=foo-bar-nm.

buildrump.sh

@@ -911,9 +911,22 @@ evaltoolchain ()
 	fi
 	MACH_ARCH=$(echo ${CC_TARGET} | sed 's/-.*//' )
 
+	#
+	# Try to figure out if we're using the native toolchain or
+	# a cross one.  Assume that a native cc doesn't have '-'
+	# in its name.  We use this information in the step below
+	# where we guess toolchain defaults.
+	#
+	basecc="$(basename ${CC})"
+	if [ "${basecc}" = "${basecc#*-}" ]; then
+		crosstools=false
+	else
+		crosstools=true
+	fi
+
 	# Set names of tools we're going to use.  try to guess them
 	# for common scenarios
-	if ${NATIVEBUILD} || ${KERNONLY}; then
+	if ${NATIVEBUILD} || ! ${crosstools}; then
 		: ${AR:=ar}
 		: ${NM:=nm}
 		: ${OBJCOPY:=objcopy}