libsframe: use appropriate data types for args of sframe_encode

include/
	* sframe-api.h (sframe_encode): Use of uint8_t is more
	appropriate.
libsframe/
	* sframe.c (sframe_encode): Likewise.
diff --git a/include/sframe-api.h b/include/sframe-api.h
index 4661492..9cb2db0 100644
--- a/include/sframe-api.h
+++ b/include/sframe-api.h
@@ -202,7 +202,7 @@
 /* Create an encoder context with the given SFrame format version VER, FLAGS
    and ABI information.  Sets errp if failure.  */
 extern sframe_encoder_ctx *
-sframe_encode (unsigned char ver, unsigned char flags, int abi,
+sframe_encode (uint8_t ver, uint8_t flags, uint8_t abi_arch,
 	       int8_t fixed_fp_offset, int8_t fixed_ra_offset, int *errp);
 
 /* Free the encoder context.  */
diff --git a/libsframe/sframe.c b/libsframe/sframe.c
index b885e3d..40927f0 100644
--- a/libsframe/sframe.c
+++ b/libsframe/sframe.c
@@ -1248,10 +1248,11 @@
 }
 
 /* Create an encoder context with the given SFrame format version VER, FLAGS
-   and ABI information.  Sets errp if failure.  */
+   and ABI information.  Uses the ABI specific FIXED_FP_OFFSET and
+   FIXED_RA_OFFSET values as provided.  Sets errp if failure.  */
 
 sframe_encoder_ctx *
-sframe_encode (unsigned char ver, unsigned char flags, int abi_arch,
+sframe_encode (uint8_t ver, uint8_t flags, uint8_t abi_arch,
 	       int8_t fixed_fp_offset, int8_t fixed_ra_offset, int *errp)
 {
   sframe_header *hp;