d/rules: Export variables instead of setting them through $MAKEFLAGS.

The latter doesn't work as of GNU Make 4.4.1.

Closes: #1089264

1 files changed, 2 insertions, 1 deletions

diff --git a/debian/rules b/debian/rules
index 0234c6a..36a24cd 100755
--- a/debian/rules
+++ b/debian/rules
@@ -1,6 +1,7 @@
 #!/usr/bin/make -f
 
-MAKEFLAGS = prefix=/usr sitelib=/usr/share/perl5
+export prefix=/usr
+export sitelib=$(prefix)/share/perl5
 
 %:
 	dh $@