lib/bug: BUGerr(err) - like BUGe() but takes error code explicitly

We'll need this for function which return error not in errno - e.g.
pthread_sigmask().

include/wendelin/bug.h

@@ -36,6 +36,10 @@
     __bug(__FILE__, __LINE__, __func__);            \
 } while (0)
 
+#define BUGerr(err) do {                            \
+    __bug_err(__FILE__, __LINE__, __func__, err);   \
+} while (0)
+
 #define BUGe() do {                                 \
     __bug_errno(__FILE__, __LINE__, __func__);      \
 } while (0)
@@ -57,6 +61,8 @@ void __todo(const char *, const char *, unsigned, const char *)
 void __warn(const char *, unsigned, const char *, const char *);
 void __bug(const char *, unsigned, const char *)
     __attribute__((noreturn));
+void __bug_err(const char *, unsigned, const char *, int)
+    __attribute__((noreturn));
 void __bug_errno(const char *, unsigned, const char *)
     __attribute__((noreturn));
 void __bug_fail(const char *, const char *, unsigned, const char *)

lib/bug.c

@@ -43,17 +43,23 @@ void __bug(const char *file, unsigned line, const char *func)
 }
 
 
-void __bug_errno(const char *file, unsigned line, const char *func)
+void __bug_err(const char *file, unsigned line, const char *func, int err)
 {
-    char errno_buf[128];
-    char *errno_str;
+    char err_buf[128];
+    char *err_str;
 
-    errno_str = strerror_r(errno, errno_buf, sizeof(errno_buf));
-    fprintf(stderr, "%s:%u %s\tBUG! (%s)\n", file, line, func, errno_str);
+    err_str = strerror_r(err, err_buf, sizeof(err_buf));
+    fprintf(stderr, "%s:%u %s\tBUG! (%s)\n", file, line, func, err_str);
     abort();
 }
 
 
+void __bug_errno(const char *file, unsigned line, const char *func)
+{
+    __bug_err(file, line, func, errno);
+}
+
+
 void __warn(const char *file, unsigned line, const char *func, const char *msg)
 {
     fprintf(stderr, "%s:%u %s WARN: %s\n", file, line, func, msg);