Pass back errno if fread fails

To more accurately mimic open() with fopen() we need to make i negative so errno gets reported.
Trim unnecessary library from MD5 makefile

Sources/md5/Makefile

@@ -31,7 +31,7 @@
 COMPONENT  = MD5
 INSTTYPE   = app
 OBJS       = md5 md5c mdXhl
-LIBS       = ${UNIXLIB} ${SOCK5LIB}
+LIBS       = ${UNIXLIB}
 CINCLUDES  = -ITCPIPLibs:,C:
 CDEFINES   = -DRISCOS_TWEAK
 

Sources/md5/c/mdXhl

@@ -96,8 +96,10 @@ MDXFileChunk(const char *filename, char *buf, off_t ofs, off_t len)
 	while (n > 0) {
 #ifdef RISCOS_TWEAK
 		i = MIN(n, sizeof(buffer));
-		if (fread(buffer, sizeof(unsigned char), i, handle) != i)
+		if (fread(buffer, sizeof(unsigned char), i, handle) != i) {
+			i = -1;
 			break;
+		}
 #else
 		if (n > sizeof(buffer))
 			i = read(f, buffer, sizeof(buffer));