[jhbuild] install: add a remark about last patch

[Paolo Borelli <pborelli src gnome org>]

commit 8391469b31c356077222c1119e526d7980de60df
Author: Paolo Borelli <pborelli gnome org>
Date:   Tue Sep 17 19:04:29 2013 +0200

    install: add a remark about last patch
    
    Otherwise it is quite possible that we reintroduce it with a "clean up"

 Makefile.plain |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.plain b/Makefile.plain
index e90813b..224d789 100644
--- a/Makefile.plain
+++ b/Makefile.plain
@@ -41,6 +41,7 @@ install: include-check install-check
 # if ~/bin/jbuild exists, it is most likely an old version, and it will
 # not work; so rename it and install a symlink to the new version
 # instead.
+# (This comment is intentionally not indented, otherwise make prints it)
        @if [ -e "$(HOME)/bin/jhbuild" ] && [ ! $(bindir) -ef $(HOME)/bin ]; then \
                mv "$(HOME)/bin/jhbuild" "$(HOME)/bin/jhbuild.old" ; \
                ln -s $(bindir)/jhbuild "$(HOME)/bin/jhbuild" ; \