Move test file into opam package

Author: bobot

packages/conf-flint/conf-flint.3.0/files/test.c

@@ -4,6 +4,7 @@ homepage: "http://flint.org"
 bug-reports: "https://github.com/flintlib/flint2.git"
 license: "LGPL-2.1-only"
 build: [
+  ["sh" "-exc" "echo \"#include  <flint/flint.h>\\n#if __FLINT_VERSION < 3\\n#error \\\"Flint (>= 3.0) is not accessible\\\"\\n#endif\" > test.c"]
   ["sh" "-exc" "cc -c $CFLAGS -I/usr/local/include test.c"] {os != "macos" & os != "win32"}
   [
 		"sh"
@@ -28,6 +29,7 @@ depexts: [
   ["flint-devel"] {os-family = "suse"}
   ["libflint-devel"] {os = "win32" & os-distribution = "cygwinports"}
   ["flint"] {os-distribution = "nixos"}
+  ["flint"] {os-distribution = "arch"}
 ]
 synopsis: "Virtual package relying on a Flint lib system installation"
 description: