gitian: use CONFIG_SITE rather than hijacking the prefix

contrib/gitian-descriptors/gitian-osx.yml

@@ -96,7 +96,7 @@ script: |
 
   # Create the release tarball using (arbitrarily) the first host
   ./autogen.sh
-  ./configure --prefix=${BASEPREFIX}/`echo "${HOSTS}" | awk '{print $1;}'`
+  CONFIG_SITE=${BASEPREFIX}/`echo "${HOSTS}" | awk '{print $1;}'`/share/config.site ./configure --prefix=/
   make dist
   SOURCEDIST=`echo bitcoin-*.tar.gz`
   DISTNAME=`echo ${SOURCEDIST} | sed 's/.tar.*//'`
@@ -118,9 +118,9 @@ script: |
     mkdir -p ${INSTALLPATH}
     tar --strip-components=1 -xf ../$SOURCEDIST
 
-    ./configure --prefix=${BASEPREFIX}/${i} --bindir=${INSTALLPATH}/bin --includedir=${INSTALLPATH}/include --libdir=${INSTALLPATH}/lib --disable-ccache --disable-maintainer-mode --disable-dependency-tracking ${CONFIGFLAGS}
+    CONFIG_SITE=${BASEPREFIX}/${i}/share/config.site ./configure --prefix=/ --disable-ccache --disable-maintainer-mode --disable-dependency-tracking ${CONFIGFLAGS}
     make ${MAKEOPTS}
-    make install-strip
+    make install-strip DESTDIR=${INSTALLPATH}
 
     make deploydir
     mkdir -p unsigned-app-${i}