New function: strerror

* configure (have_strerror_r): New variable.
Detect whether we have strerror_r and which flavor:
GNU or POSIX. Define HAVE_STRERROR_GNU or HAVE_STRERROR_POSIX
in config.h.

* sysif.c (strerror_wrap): New function.
(sysif_init): Register strerror intrinsic.

* txr.1: Documented.

1 files changed, 17 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index 8d30662c..229d50ae 100644
--- a/txr.1
+++ b/txr.1
@@ -58584,6 +58584,23 @@ The place form of
 .code errno
 does not take an argument.
 
+.coNP Function @ strerror
+.synb
+.mets (strerror << errno-value )
+.syne
+.desc
+The
+.code strerror
+returns a character string which provides the host platform's description
+of the integer
+.meta errno-value
+obtained from the
+.code errno
+function.
+
+If the host platform fails to provide a descripion, the function returns
+.codn nil .
+
 .coNP Function @ exit
 .synb
 .mets (exit << status )