--- a/nx-X11/Makefile
+++ b/nx-X11/Makefile
@@ -70,7 +70,7 @@
 	else \
 	    exit 0; \
 	fi
-	which $(IMAKE) 1>/dev/null && $(IMAKE_CMD) $(MFLAGS) -s xmakefile -DTOPDIR=$(TOP) -DCURDIR=$(CURRENT_DIR)
+	command -v $(IMAKE) 1>/dev/null && $(IMAKE_CMD) $(MFLAGS) -s xmakefile -DTOPDIR=$(TOP) -DCURDIR=$(CURRENT_DIR)
 
 # don't allow any default rules in this Makefile
 .SUFFIXES:
--- a/nx-X11/extras/Mesa_6.4.2/bin/mklib
+++ b/nx-X11/extras/Mesa_6.4.2/bin/mklib
@@ -285,7 +285,7 @@
 		# -linker was not specified, choose default linker now
 		if [ $CPLUSPLUS = 1 ] ; then
 		    # determine linker and options for C++ code
-		    if [ `which c++` ] ; then
+		    if [ `command -v c++` ] ; then
 			# use Sun c++
 			LINK="c++"
 		    elif [ `type g++` ] ; then