make configure work even when no prefix is specified

git-svn-id: svn://svn.oetiker.ch/rrdtool/branches/1.2@353 a5681a0c-68f1-0310-ab6d-d61299d08faa

diff --git a/program/configure.ac b/program/configure.ac
index 5cfd7d284ba16eb7c8821955046dbfa94567a57f..d6ad88abfa3e75ed1f7c38ece7d14364ad1efa6e 100644 (file)
--- a/program/configure.ac
+++ b/program/configure.ac
@@ -309,7 +309,10 @@ AC_MSG_CHECKING(Perl Modules to build)
 AC_MSG_RESULT(${COMP_PERL:-No Perl Modules will be built})
 
 # Options to pass when configuring perl module
-PERL_MAKE_OPTIONS="PREFIX=$prefix LIB=$prefix/lib/perl/$PERL_VERSION"
+ppref=$prefix
+test "x$ppref" = xNONE && ppref=$ac_default_prefix
+
+PERL_MAKE_OPTIONS="PREFIX=$ppref LIB=$ppref/lib/perl/$PERL_VERSION"
 
 dnl pass additional perl options when generating Makefile from Makefile.PL
 AC_ARG_ENABLE(perl-site-install,