diff --git a/LOG b/LOG
index 8a4c5fb56e..c211abd927 100644
--- a/LOG
+++ b/LOG
@@ -943,4 +943,6 @@
   invisible due to libs-visible? flag.
     compile.ss, 7.ms, root-experr-compile-0-f-f-f, root-experr-compile-2-f-f-f,
     patch-compile-0-f-t-f, patch-compile-0-t-f-f, patch-interpret-0-f-f-f,
-    patch-interpret-0-f-t-f, patch-interpret-3-f-f-f, patch-interpret-3-f-t-f
\ No newline at end of file
+    patch-interpret-0-f-t-f, patch-interpret-3-f-f-f, patch-interpret-3-f-t-f
+- Double FMTBUFSIZE to fix compilation with gcc-8
+    c/prim5.c
\ No newline at end of file
diff --git a/c/prim5.c b/c/prim5.c
index 5bee635c00..69c6bfdfa6 100644
--- a/c/prim5.c
+++ b/c/prim5.c
@@ -219,7 +219,7 @@ static ptr s_decode_float(x) ptr x; {
     return S_decode_float(FLODAT(x));
 }
 
-#define FMTBUFSIZE 60
+#define FMTBUFSIZE 120
 #define CHUNKADDRLT(x, y) (((chunkinfo *)(Scar(x)))->addr < ((chunkinfo *)(Scar(y)))->addr)
 mkmergesort(sort_chunks, merge_chunks, ptr, Snil, CHUNKADDRLT, INITCDR)