bootstrap: Use a link to distro file instead of a copy.

extras/contrib/bootstrap

@@ -149,14 +149,6 @@ rm -f "${config_mak}"
     echo "# Make changes if you know what you're doing."
 } > "${config_mak}"
 
-# Create distro.mak
-distro_mak="${BUILDDIR}/distro.mak"
-rm -f "${distro_mak}"
-{
-    echo "# Automatically generated by bootstrap"
-    echo "# Make changes if you know what you're doing."
-} > "${distro_mak}"
-
 if test "$TARGET" != "$BUILD"; then
     test -z "$CC"    && CC="${TARGET}-gcc"
     test -z "$CXX"   && CXX="${TARGET}-g++"
@@ -312,7 +304,10 @@ fi
 # Default Unix-like systems
 hint_distro unix
 
-cat src/Distributions/"${DISTRO}".mak >> "${distro_mak}"
+distro_mak="${BUILDDIR}/distro.mak"
+distro_file="`pwd`/src/Distributions/${DISTRO}.mak"
+rm "${distro_mak}"
+ln -sf "${distro_file}" "${distro_mak}"
 
 #
 # Distro specific settings