Don't try to use acct() on cygwin (which doesn't support it). Fixes: #111

util/int/moncalls.c

@@ -47,6 +47,14 @@ struct timeb {			/* non-existing; we use an ad-hoc definition */
 #include	"warn.h"
 #include	"mem.h"
 
+/* Detect supported system calls. */
+
+#if !defined __CYGWIN__
+#define HAS_ACCT 1
+#else
+#define HAS_ACCT 0
+#endif
+
 #define	INPUT		0
 #define	OUTPUT		1
 
@@ -914,6 +922,7 @@ moncall()
 	case 51:			/* Acct */
 
 		dsp1 = pop_ptr();
+		#if HAS_ACCT
 			if (!savestr(0, dsp1) || acct(buf[0]) == -1) {
 				push_err();
 				LOG(("@m4 Acct: failed, dsp1 = %lu, errno = %d",
@@ -923,6 +932,12 @@ moncall()
 				push_int(0);
 				LOG(("@m9 Acct: succeeded, dsp1 = %lu", dsp1));
 			}
+		#else
+			einval(WMPXIMP);
+			push_err();
+			LOG(("@m4 Acct: failed, request = %d, dsp1 = %lu, errno = %d",
+				request, dsp1, errno));
+		#endif
 		break;
 
 	case 54:			/* Ioctl */