compatibility: replace iscntrl with own ISCNTRL macro

It is unspecified if the C locale iscntrl is compatible with ASCII or not.

Noticed when testing on OpenBSD 3.8 which uses extended ASCII and also uses the
C1 range for control-characters.  This breaks support with UTF-8.

Reference:
https://en.wikipedia.org/wiki/C0_and_C1_control_codes#C1_control_codes_for_general_use
C1 table.

Force an own definition of an ASCII-compatible control-character range since
sfeed expects input to be UTF-8 (or converted from iconv) and so output to be
UTF-8 aswell.

1 files changed, 3 insertions, 0 deletions

diff --git a/util.h b/util.h
index 7923cdc..c68cef4 100644
--- a/util.h
+++ b/util.h
@@ -8,6 +8,9 @@
 #define unveil(p1,p2) 0
 #endif
 
+/* control-character in the ASCII range 0-127: compatible with UTF-8 */
+#define ISCNTRL(c) ((c) < ' ' || (c) == 0x7f)
+
 #undef strcasestr
 char *strcasestr(const char *, const char *);
 #undef strlcat