build/pkgs/flint: Reject FLINT >= 3.1.0

Author: Matthias Koeppe

build/pkgs/flint/spkg-configure.m4

@@ -1,11 +1,26 @@
 SAGE_SPKG_CONFIGURE([flint], [
     SAGE_SPKG_DEPCHECK([mpfr], [
-        AC_CHECK_HEADER(flint/flint.h, [
+        AC_CHECK_HEADER(flint/flint.h, [dnl
           dnl gr_get_fexpr appears in Flint 3.0
-          AC_SEARCH_LIBS([gr_get_fexpr], [flint], [], [sage_spkg_install_flint=yes])
+          AC_SEARCH_LIBS([gr_get_fexpr], [flint], [dnl
+            dnl Flint 3.1 is too new
+            AC_MSG_CHECKING([whether FLINT version is >= 3.1.0])
+            AC_COMPILE_IFELSE([dnl
+              AC_LANG_PROGRAM([[#include <flint/flint.h>
+                                #if __FLINT_RELEASE >= 30100
+                                # error "FLINT 3.1 is too new"
+                                #endif
+                              ]])
+            ], [dnl
+              AC_MSG_RESULT([no])
+            ], [dnl
+              AC_MSG_RESULT([yes; too new])
+              sage_spkg_install_flint=yes
+            ])
+          ], [sage_spkg_install_flint=yes])
         ], [sage_spkg_install_flint=yes])
     ])
-], [], [], [
+], [], [], [dnl
      if test x$sage_spkg_install_flint = xyes; then
         AC_SUBST(SAGE_FLINT_PREFIX, ['$SAGE_LOCAL'])
      else