flux: ensure flux_job_timeleft() is available

flux_job_timeleft() was introduced in flux-core 0.47.0, so check the
flux-core version in the spec file, and check the function is available
when configure is run.

config/x_ac_flux_job_timeleft.m4

@@ -0,0 +1,30 @@
+##*****************************************************************************
+#  SYNOPSIS:
+#    X_AC_FLUX_JOB_TIMELEFT()
+#
+#  DESCRIPTION:
+#    Check flux_job_timeleft() is present
+##*****************************************************************************
+
+AC_DEFUN([X_AC_FLUX_JOB_TIMELEFT], [
+  AS_IF([test "$FLUX_LIBADD"],[
+    AC_MSG_CHECKING([Whether flux_job_timeleft() is present.])
+    LIBS="$FLUX_LIBS $FLUX_LIBADD $LIBS"
+    AC_LINK_IFELSE([
+      AC_LANG_PROGRAM(
+        [[#include <flux/core.h>]],
+        [[double tl = flux_job_timeleft(NULL, NULL, NULL);]]
+      )],
+      [x_ac_cv_flux_job_timeleft=1],
+      [x_ac_cv_flux_job_timeleft=0]
+    )
+    AS_IF([test "x$x_ac_cv_flux_job_timeleft" = x1],
+      [AC_MSG_RESULT([yes])],
+      [
+        AC_MSG_RESULT([no])
+        AC_MSG_ERROR([flux_job_timeleft() is required.  Update to a newer flux or use --without-flux.])
+      ]
+    )
+  ])
+
+])

configure.ac

@@ -46,6 +46,7 @@ X_AC_LCRM
 X_AC_MOAB
 X_AC_LSF
 X_AC_FLUX
+X_AC_FLUX_JOB_TIMELEFT
 
 aix_64bit_mode=no
 using_aix=no

libyogrt.spec.in

@@ -85,7 +85,7 @@ SLURM plugin for libyogrt
 %package flux
 Summary: libyogrt plugin for Flux
 Group: System Environment/Base
-BuildRequires: flux-core
+BuildRequires: flux-core >= 0.47.0
 Requires: flux-core
 Requires: libyogrt = %{version}
 %description flux