diff --git a/libgdither.spec b/libgdither.spec
index 28e0f55..2c00920 100644
--- a/libgdither.spec
+++ b/libgdither.spec
@@ -1,6 +1,6 @@
 Name:           libgdither
 Version:        0.6
-Release:        19%{?dist}
+Release:        20%{?dist}
 Summary:        Library for applying dithering to PCM audio sources
 
 License:        GPLv2+
@@ -40,11 +40,12 @@ developing applications that use %{name}.
 %build
 export INIT_CFLAGS="${RPM_OPT_FLAGS}"
 export LDFLAGS="%{build_ldflags}"
+export PREFIX="%{_prefix}"
 %make_build
 
 
 %install
-%make_install LIBDIR=%{_libdir}
+%make_install PREFIX=%{_prefix} LIBDIR=%{_libdir}
 find $RPM_BUILD_ROOT -name '*.la' -exec rm -f {} ';'
 
 sed -i -e 's|/usr/local|%{_prefix}|g' \
@@ -70,6 +71,9 @@ make test CFLAGS="%{optflags} -Werror --std=c99 -I%{_builddir}/%{?buildsubdir}"
 %{_libdir}/pkgconfig/libgdither.pc
 
 %changelog
+* Sun May 26 2019 David King <amigadave@amigadave.com> - 0.6-20
+- Pass through PREFIX to build system
+
 * Fri Feb 01 2019 Fedora Release Engineering <releng@fedoraproject.org> - 0.6-19
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_30_Mass_Rebuild