diff --git a/configure.ac b/configure.ac
index c1ad547..f971597 100644
--- a/configure.ac
+++ b/configure.ac
@@ -19,7 +19,7 @@ fi
 
 AC_CANONICAL_HOST
 AM_CONDITIONAL(LD_ISCSI,
-               [case $host_os in linux*) ;; *) AS_SET_STATUS(1);; esac ])
+               [expr "$host_os" : linux > /dev/null 2>&1])
 
 if test "$ac_cv_prog_gcc" = yes; then
    WARN_CFLAGS="-Wall -W -Wshadow -Wstrict-prototypes -Wpointer-arith -Wcast-align -Wwrite-strings"
diff --git a/m4/.gitignore b/m4/.gitignore
index 94e6f26..764b428 100644
--- a/m4/.gitignore
+++ b/m4/.gitignore
@@ -1,5 +1,5 @@
 /libtool.m4
+/lt~obsolete.m4
 /ltoptions.m4
 /ltsugar.m4
 /ltversion.m4
-/lt~obsolete.m4