diff --git a/util/cgg/bootlex.l b/util/cgg/bootlex.l
index ec796a578..261467664 100644
--- a/util/cgg/bootlex.l
+++ b/util/cgg/bootlex.l
@@ -18,6 +18,9 @@
 #include "booth.h"
 #include "y.tab.h"
 
+/* fileno is not C89 and can be missing sometimes. */
+int fileno(FILE *stream);
+
 int lineno = 1;
 extern char *iname;
 %}
diff --git a/util/cgg/main.c b/util/cgg/main.c
index 186bbc966..fe80edd27 100644
--- a/util/cgg/main.c
+++ b/util/cgg/main.c
@@ -24,6 +24,8 @@ void outbyte(int n);
 void patbyte(int n);
 void hashpatterns();
 
+#define IsAscii(_c) (((_c) & ~0x7f) == 0)
+
 char * myalloc(int n)
 {
 	register char *p;
@@ -604,7 +606,7 @@ void finishio()
 		fprintf(cfile,"\t\"");
 		while (*p) {
 			register int c = (*p) & BMASK;
-			if (! isascii(c) || iscntrl(c)) {
+			if (! IsAscii(c) || iscntrl(c)) {
 				/* The next line used to have (c>>6)&03,
 				   but this triggered a bug in GCC 2.4.5
 				   on SPARC.