test: add #require flint? for the test suite.

check/README.md

@@ -210,6 +210,8 @@ The following methods are available in Ruby test programs.
   `true` if FORM is the multithreaded version (TFORM), otherwise `false`.
 - `mpi? → bool`  
   `true` if FORM is the MPI version (ParFORM), otherwise `false`.
+- `flint? → bool`  
+  `true` if FORM was built with FLINT support, otherwise `false`.
 - `valgrind? → bool`  
   `true` if FORM is running under Valgrind, otherwise `false`.
 - `wordsize → integer`  

check/check.rb

@@ -310,6 +310,10 @@ def mpi?
     FormTest.cfg.mpi?
   end
 
+  def flint?
+    FormTest.cfg.flint?
+  end
+
   def valgrind?
     if FormTest.cfg.fake_valgrind.nil?
       !FormTest.cfg.valgrind.nil?
@@ -1249,6 +1253,7 @@ def initialize(form, mpirun, mpirun_opts, valgrind, valgrind_opts, fake_valgrind
     @is_serial   = nil
     @is_threaded = nil
     @is_mpi      = nil
+    @has_flint   = nil
     @wordsize    = wordsize
     @form_cmd    = nil
   end
@@ -1268,6 +1273,10 @@ def mpi?
     @is_mpi
   end
 
+  def flint?
+    @has_flint
+  end
+
   def check_bin(name, bin)
     # Check if the executable is available.
     if File.executable?(bin)
@@ -1326,6 +1335,17 @@ def check
         system("#{form_bin} #{frmname}")
         fatal("failed to get the version of '#{@form}'")
       end
+      # Check if Flint is available.
+      # Use form -vv which contains either "+flint=VERSION" or "-flint".
+      feature_out, _status = Open3.capture2e(@form_bin, "-vv")
+      if feature_out =~ /(?:^|\s)\+flint(?:=|\s|$)/
+        @has_flint = true
+      elsif feature_out =~ /(?:^|\s)-flint(?:\s|$)/
+        @has_flint = false
+      else
+        warn("failed to determine FLINT support of '#{@form}'")
+        @has_flint = false
+      end
       # Check the wordsize.
       # Method 1: from the output header.
       # Method 2: 2^64 = 0 (mod 2^64) => 64-bit machine => sizeof(WORD) = 4, etc.