diff --git a/perl-Crypt-DH.spec b/perl-Crypt-DH.spec
index 25c5db4..a095cda 100644
--- a/perl-Crypt-DH.spec
+++ b/perl-Crypt-DH.spec
@@ -4,7 +4,7 @@
 Summary:	Perl module implementing the Diffie-Hellman key exchange system
 Name:		perl-Crypt-DH
 Version:	0.06
-Release:	8%{?dist}
+Release:	9%{?dist}
 License:	GPL+ or Artistic
 Group:		Development/Libraries
 Url:		http://search.cpan.org/dist/Crypt-DH/
@@ -14,6 +14,16 @@ Requires:	perl(:MODULE_COMPAT_%(eval "`%{__perl} -V:version`"; echo $version))
 BuildArch:	noarch
 BuildRequires:	perl(ExtUtils::MakeMaker), perl(Test::More)
 
+# Pull in Math::BigInt::GMP for GMP support for suitably recent versions of Math::BigInt
+# else use Math::GMP
+%if %(%{__perl} -MMath::BigInt -e 'use Math::BigInt 1.87;' 2>/dev/null && echo 1 || echo 0)
+BuildRequires:	perl(Math::BigInt::GMP)
+Requires:	perl(Math::BigInt::GMP)
+%else
+BuildRequires:	perl(Math::GMP)
+Requires:	perl(Math::GMP)
+%endif
+
 %description
 Crypt::DH is a Perl implementation of the Diffie-Hellman key exchange system.
 Diffie-Hellman is an algorithm by which two parties can agree on a shared
@@ -48,8 +58,12 @@ private keys, between them.
 %{_mandir}/man3/Crypt::DH.3pm*
 
 %changelog
+* Tue Nov  4 2008 Paul Howarth <paul@city-fan.org> 0.06-9
+- BuildRequire and Require a GMP support module, either Math::GMP or
+  Math::BigInt::GMP depending on how recent Math::BigInt is
+
 * Thu Mar  6 2008 Tom "spot" Callaway <tcallawa@redhat.com> 0.06-8
-- rebuild for new perl
+- Rebuild for new perl
 
 * Sat Aug 11 2007 Paul Howarth <paul@city-fan.org> 0.06-7
 - Clarify license as GPL v1 or later, or Artistic (same as perl)