diff --git a/kpack_c.c b/kpack_c.c
index 1645fd1..f932aff 100644
--- a/kpack_c.c
+++ b/kpack_c.c
@@ -31,7 +31,7 @@ unsigned byteswap(unsigned val)
     return (val << 16) | (val >> 16);
 }
 
-unsigned pack_lzma(unsigned char *infile, unsigned char *outfile, unsigned insize, unsigned char *workmem, unsigned is_kerpack)
+unsigned pack_lzma(unsigned char *infile, unsigned char *outfile, unsigned insize, unsigned char *workmem, int is_kerpack)
 {
     unsigned outsize = lzma_compress(infile, outfile + 11, insize, workmem, is_kerpack);
     unsigned tmp = 0;