Fix building on Perl without "." in @INC

This is implemented by unbundling ./inc modules.

perl-Module-Signature.spec

@@ -1,6 +1,6 @@
 Name:           perl-Module-Signature
 Version:        0.81
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        CPAN signature management utilities and modules
 License:        CC0
 URL:            http://search.cpan.org/dist/Module-Signature/
@@ -12,9 +12,14 @@ BuildRequires:  findutils
 BuildRequires:  make
 BuildRequires:  perl
 BuildRequires:  perl-generators
-BuildRequires:  perl(base)
-BuildRequires:  perl(Cwd)
-BuildRequires:  perl(ExtUtils::MakeMaker)
+BuildRequires:  perl(inc::Module::Install) >= 0.92
+BuildRequires:  perl(Module::Install::Can)
+BuildRequires:  perl(Module::Install::External)
+BuildRequires:  perl(Module::Install::Makefile)
+BuildRequires:  perl(Module::Install::Metadata)
+BuildRequires:  perl(Module::Install::Scripts)
+BuildRequires:  perl(Module::Install::WriteAll)
+BuildRequires:  sed
 # Module runtime
 BuildRequires:  gnupg2
 BuildRequires:  perl(constant)
@@ -50,6 +55,9 @@ SIGNATURE files for Perl CPAN distributions.
 
 %prep
 %setup -q -n Module-Signature-%{version}
+# Remove bundled modules
+rm -r ./inc/*
+sed -i -e '/^inc\//d' MANIFEST
 
 # Create a GPG directory for testing, to avoid using ~/.gnupg
 mkdir --mode=0700 gnupghome
@@ -76,6 +84,9 @@ make test
 %{_mandir}/man3/Module::Signature.3*
 
 %changelog
+* Wed May 17 2017 Petr Pisar <ppisar@redhat.com> - 0.81-4
+- Fix building on Perl without "." in @INC (CPAN RT#120405)
+
 * Wed Apr  5 2017 Paul Howarth <paul@city-fan.org> - 0.81-3
 - Use gnupg2 rather than gnupg (#1439089)
 - Drop EL-5 support