Lose hope of running against guile 2.2 or earlier.

We have previously allowed versions 2.0 and 2.2 to get past the configure
stage, but all versions of guile before 3.0 have in fact failed to compile the
code due to syntax errors for some time now.

* build-aux/guix.scm:  package depends on guile@3
* configure.ac:  only look for guile version 3
* src/mcron/base.scm:  drop allowance for old-fashioned (version 2.0) select

3 files changed, 14 insertions, 28 deletions

diff --git a/build-aux/guix.scm b/build-aux/guix.scm
index 1b3d449..d452a37 100644
--- a/build-aux/guix.scm
+++ b/build-aux/guix.scm
@@ -45,7 +45,7 @@
   (source (local-file (dirname %srcdir) #:recursive? #t
                       #:select? keep-mcron-file?))
   (inputs
-   `(("guile" ,(specification->package "guile@2.2"))))
+   `(("guile" ,(specification->package "guile@3"))))
   (native-inputs
    `(("autoconf" ,(specification->package "autoconf"))
      ("automake" ,(specification->package "automake"))
diff --git a/configure.ac b/configure.ac
index 0f7cfda..451777d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -43,7 +43,7 @@ m4_pattern_allow([^GUILE_PKG])
 m4_pattern_allow([^GUILE_PROGS])
 
 # Check for latest Guile development files.
-GUILE_PKG([3.0 2.2 2.0])
+GUILE_PKG([3.0])
 
 # Checks for programs.
 GUILE_PROGS
diff --git a/src/mcron/base.scm b/src/mcron/base.scm
index 79a88a6..a8250ca 100644
--- a/src/mcron/base.scm
+++ b/src/mcron/base.scm
@@ -397,16 +397,16 @@ of CHILDREN-DATA."
   (define (match-collected-pid? job-data)
     (= (job-data:pid job-data) collected-pid))
 
-  (if (and has-children?
-           (not (= 0 collected-pid)))   ;at least one process was collected
-      (begin
-        (update-number-children! 1-)
-        ;; Fully collect the output of the reaped child process.
-        (and=> (find match-collected-pid? children-data)
-               (lambda (child-data)
-                 (process-output (list child-data))))
-        (child-cleanup (remove match-collected-pid? children-data)))
-      children-data))
+  (cond ((and has-children?
+              (not (= 0 collected-pid)))   ;at least one process was collected
+         (update-number-children! 1-)
+         ;; Fully collect the output of the reaped child process.
+         (and=> (find match-collected-pid? children-data)
+                (lambda (child-data)
+                  (process-output (list child-data))))
+         (child-cleanup (remove match-collected-pid? children-data)))
+        (else
+         children-data)))
 
 (define* (run-job-loop #:optional (fd-list '())
                        #:key (schedule %global-schedule))
@@ -423,20 +423,6 @@ infinitum."
   ;; case we break out of the loop here, and let the main procedure deal with
   ;; the situation (it will eventually re-call this function, thus maintaining
   ;; the loop).
-  (cond-expand
-    ((or guile-3.0 guile-2.2)                     ;2.2 and 3.0
-     (define select* select))
-    (else
-     ;; On Guile 2.0, 'select' could throw upon EINTR or EAGAIN.
-     (define (select* read write except time)
-       (catch 'system-error
-         (lambda ()
-           (select read write except time))
-         (lambda args
-           (if (member (system-error-errno args) (list EAGAIN EINTR))
-               '(() () ())
-               (apply throw args)))))))
-
   (let/ec break
     (let loop ((children-data '()))     ;list of <job-data> objects
       (match (find-next-jobs #:schedule schedule)
@@ -452,8 +438,8 @@ infinitum."
                                                   (port->fdes p)))
                                            ports)))
            (when (> sleep-time 0)
-             (match (select* (append fd-list children-fdes)
-                             '() '() sleep-time)
+             (match (select (append fd-list children-fdes)
+                            '() '() sleep-time)
                ((() () ())
                 ;; 'select' returned an empty set, perhaps because it got
                 ;; EINTR or EAGAIN.