diff --git a/src/lwp/Makefile.in b/src/lwp/Makefile.in
index 0bf1b4c6d0..654a430515 100644
--- a/src/lwp/Makefile.in
+++ b/src/lwp/Makefile.in
@@ -37,7 +37,7 @@ process.o	: process.s process.c
 	pmax_he1) \
 		$(CC) -c -I${TOP_INCDIR} process.s;; \
 	sun4c_51 | sun4c_52 | sun4m_51 | sun4m_52 | sun4c_53 | sun4m_53  | sun4_53 | sun4_52 | sun4_54 | sun4c_54 | sun4m_54 | sun4x_5? | sunx86_5?) \
-		/usr/ccs/lib/cpp -P -I${TOP_INCDIR} process.s process.ss; \
+		/usr/ccs/lib/cpp -P -I${TOP_INCDIR} ${srcdir}/process.s process.ss; \
 		${AS} process.ss -o process.o; \
 			$(RM) process.ss ;; \
 	sgi_5* ) \
diff --git a/src/sys/Makefile.in b/src/sys/Makefile.in
index afbd0da73c..a7bf5c1b39 100644
--- a/src/sys/Makefile.in
+++ b/src/sys/Makefile.in
@@ -44,7 +44,7 @@ tests:	pagsh pagsh.krb fixit iinc idec icreate iopen istat rmtsysd
 syscall.o: syscall.s
 	case "$(SYS_NAME)" in \
 	 sun4c_51 | sun4c_52 | sun4m_51 | sun4m_52 | sun4c_53 | sun4m_53  | sun4_53 | sun4_52 | sun4_54 | sun4c_54 | sun4m_54 | sun4x_5? | sunx86_5?) \
-		/usr/ccs/lib/cpp  ${SFLAGS} syscall.s syscall.ss; \
+		/usr/ccs/lib/cpp  ${SFLAGS} ${srcdir}/syscall.s syscall.ss; \
 		as -o syscall.o syscall.ss;		\
 		$(RM) syscall.ss;;				\
 	 sgi_* |ppc_darwin* ) \