PR modula2/110779 SysClock can not read the clock (Darwin portability fixes)

This patch adds corrections to defensively check against glibc functions,
structures and contains fallbacks.  These fixes were required under Darwin.

gcc/m2/ChangeLog:

	PR modula2/110779
	* gm2-libs-iso/SysClock.mod (EpochTime): New procedure.
	(GetClock): Call EpochTime if the C time functions are
	unavailable.
	* gm2-libs-iso/wrapclock.def (istimezone): New function
	definition.

libgm2/ChangeLog:

	PR modula2/110779
	* configure: Regenerate.
	* configure.ac: Provide special case test for Darwin cross
	configuration.
	(GLIBCXX_CONFIGURE): New statement.
	(GLIBCXX_CHECK_GETTIMEOFDAY): New statement.
	(GLIBCXX_ENABLE_LIBSTDCXX_TIME): New statement.
	* libm2iso/wrapclock.cc: New sys/time.h conditional include.
	(sys/syscall.h): Conditional include.
	(unistd.h): Conditional include.
	(GetTimeRealtime): Re-implement.
	(SetTimeRealtime): Re-implement.
	(timezone): Re-implement.
	(istimezone): New function.
	(daylight): Re-implement.
	(isdst): Re-implement.
	(tzname): Re-implement.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>

2 files changed, 38 insertions, 8 deletions

diff --git a/gcc/m2/gm2-libs-iso/SysClock.mod b/gcc/m2/gm2-libs-iso/SysClock.mod
index 3313309..56d5503 100644
--- a/gcc/m2/gm2-libs-iso/SysClock.mod
+++ b/gcc/m2/gm2-libs-iso/SysClock.mod
@@ -173,6 +173,26 @@ BEGIN
 END ExtractDate ;
 
 
+(*
+   EpochTime - assigns all fields of userData to 0 or FALSE.
+*)
+
+PROCEDURE EpochTime (VAR userData: DateTime) ;
+BEGIN
+   WITH userData DO
+      second := 0 ;
+      minute :=  0 ;
+      hour := 0 ;
+      year := 0 ;
+      month := 0 ;
+      day := 0 ;
+      fractions := 0 ;
+      zone := 0 ;
+      summerTimeFlag := FALSE
+   END
+END EpochTime ;
+
+
 PROCEDURE GetClock (VAR userData: DateTime) ;
 (* Assigns local date and time of the day to userData *)
 VAR
@@ -207,10 +227,10 @@ BEGIN
                summerTimeFlag := (isdst () = 1)
             END
          ELSE
-            HALT
+            EpochTime (userData)
          END
       ELSE
-         HALT
+         EpochTime (userData)
       END ;
       ts := KillTimespec (ts)
    END
@@ -310,13 +330,11 @@ BEGIN
                            userData.month, userData.year) ;
       offset := timezone () ;
       sec := VAL (LONGINT, sec) - offset ;
-      IF SetTimespec (ts, sec, nano) = 0
-      THEN
-         HALT
-      END ;
-      IF SetTimeRealtime (ts) # 0
+      IF SetTimespec (ts, sec, nano) = 1
       THEN
-         HALT
+         IF SetTimeRealtime (ts) = 0
+         THEN
+         END
       END ;
       ts := KillTimespec (ts)
    END
diff --git a/gcc/m2/gm2-libs-iso/wrapclock.def b/gcc/m2/gm2-libs-iso/wrapclock.def
index 1dd12e1..9f5f286 100644
--- a/gcc/m2/gm2-libs-iso/wrapclock.def
+++ b/gcc/m2/gm2-libs-iso/wrapclock.def
@@ -36,12 +36,24 @@ TYPE
    timezone - return the glibc timezone value.
               This contains the difference between UTC and the latest
               local standard time, in seconds west of UTC.
+              If the underlying timezone is unavailable and
+              clock_gettime, localtime_r, tm_gmtoff
+              is unavailable then 0 is returned.
 *)
 
 PROCEDURE timezone () : LONGINT ;
 
 
 (*
+   istimezone returns 1 if timezone in wrapclock.cc can resolve the
+              timezone value using the timezone C library call or by using
+              clock_gettime, localtime_r and tm_gmtoff.
+*)
+
+PROCEDURE istimezone () : INTEGER ;
+
+
+(*
    daylight - return the glibc daylight value.
               This variable has a nonzero value if Daylight Saving
               Time rules apply.