implement atoi so it doesn't change errno (for now)

src/kernel/build.c

@@ -179,7 +179,8 @@ int destroy_cmd(unit * u, struct order *ord)
     s = gettoken(token, sizeof(token));
 
     if (s && *s) {
-        n = atoi((const char *)s);
+        n = atoi10((const char *)s);
+
         if (n <= 0) {
             n = INT_MAX;
         }

src/util/base36.c

@@ -23,6 +23,14 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <stdlib.h>
 #include <assert.h>
 #include <ctype.h>
+#include <errno.h>
+
+int atoi10(const char *str)
+{
+    int i = atoi(str);
+    errno = 0;
+    return i;
+}
 
 int atoi36(const char *str)
 {

src/util/base36.h

@@ -31,6 +31,7 @@ extern "C" {
     const char *itoa36(int i);
     const char *itoa10(int i);
     extern int atoi36(const char *s);
+    extern int atoi10(const char *s);
     int i10toi36(int i);
 
 #ifdef __cplusplus