diff --git a/cpanspec.yml b/cpanspec.yml
index 28e16fa..2cd1530 100644
--- a/cpanspec.yml
+++ b/cpanspec.yml
@@ -20,8 +20,11 @@ patches:
 # sed on %{name}.files
 #license: SUSE-NonFree
 #skip_noarch: 1
-#custom_build: |-
-#./Build build flags=%{?_smp_mflags} --myflag
+custom_build: |-
+ export BUILDING_AS_PACKAGE=1
+ %{__perl} Makefile.PL INSTALLDIRS=vendor
+ %{__make} %{?_smp_mflags}
+
 #custom_test: |-
 #startserver && make test
 #ignore_requires: Bizarre::Module
diff --git a/perl-ExtUtils-MakeMaker.spec b/perl-ExtUtils-MakeMaker.spec
index 686eb7b..5748a41 100644
--- a/perl-ExtUtils-MakeMaker.spec
+++ b/perl-ExtUtils-MakeMaker.spec
@@ -67,9 +67,9 @@ Perl to handle Unicode filenames, which is not yet the case on Windows.
 %patch0 -p1
 
 %build
+export BUILDING_AS_PACKAGE=1
 %{__perl} Makefile.PL INSTALLDIRS=vendor
 %{__make} %{?_smp_mflags}
-
 %check
 %{__make} test