AC_SUBST only takes a single variable

--- urlgfe-1.0.2/configure.in
+++ urlgfe-1.0.2/configure.in
@@ -53,7 +53,8 @@
 	LFS_CFLAGS=`$GETCONF LFS_CFLAGS`
 	LFS_LDFLAGS=`$GETCONF LFS_LDFLAGS`
 fi
-AC_SUBST(LFS_CFLAGS LFS_LDFLAGS)
+AC_SUBST(LFS_CFLAGS)
+AC_SUBST(LFS_LDFLAGS)
 
 AC_PATH_PROG(CURL_CONFIG, curl-config)
 if test "x$CURL_CONFIG" = "x" ; then
@@ -61,7 +62,8 @@
 fi
 CURL_CFLAGS=`$CURL_CONFIG --cflags`
 CURL_LIBS=`$CURL_CONFIG --libs`
-AC_SUBST(CURL_CFLAGS CURL_LIBS)
+AC_SUBST(CURL_CFLAGS)
+AC_SUBST(CURL_LIBS)
 
 AC_PATH_PROG(PCRE_CONFIG, pcre-config)
 if test "x$PCRE_CONFIG" = "x" ; then
@@ -70,7 +72,8 @@
 
 PCRE_CFLAGS=`$PCRE_CONFIG --cflags`
 PCRE_LIBS=`$PCRE_CONFIG --libs`
-AC_SUBST(PCRE_CFLAGS PCRE_LIBS)
+AC_SUBST(PCRE_CFLAGS)
+AC_SUBST(PCRE_LIBS)
 dnl checks for requirements.  --- end ---