Use gcc -ansi -pedantic in 9c.  Fix many non-C89-isms.
diff --git a/src/cmd/file.c b/src/cmd/file.c
index 4dbf66b..f325871 100644
--- a/src/cmd/file.c
+++ b/src/cmd/file.c
@@ -541,7 +541,7 @@
 int
 long0(void)
 {
-//	Fhdr *f;
+/*	Fhdr *f; */
 	long x;
 
 	seek(fd, 0, 0);		/* reposition to start of file */