Prevent make -C gnu from installing files in /

This is done by adding a dependency on ${GNUHOSTDIST:H}/.gitignore
for both realall and realinstall targets.

Change-Id: If086a6c02ab20a8cd4bbb3597d7203cf22dce796

gnu/dist/Makefile

@@ -8,7 +8,11 @@ MODULE=	texinfo
 .include "${.CURDIR}/../../tools/Makefile.gnuhost"
 
 # Force the mapping to standard targets even when not building tools
+# We considere work to be done as soon as the fetch step is done,
+# as everything else has to be triggered from /tools or ../usr.bin
+
 .if ${USETOOLS} != "yes"
-realall: .build_done
-realinstall: .install_done
+realall realinstall: ${GNUHOSTDIST:H}/.gitignore
+
 .endif
+