Set the default PATH to the one set by login.
diff -up krb5-1.9/src/clients/ksu/Makefile.in.ksu-path krb5-1.9/src/clients/ksu/Makefile.in
--- krb5-1.9/src/clients/ksu/Makefile.in.ksu-path 2010-03-05 10:58:25.000000000 -0500
+++ krb5-1.9/src/clients/ksu/Makefile.in 2010-03-05 10:58:25.000000000 -0500
@@ -1,6 +1,6 @@
mydir=clients$(S)ksu
BUILDTOP=$(REL)..$(S)..
-DEFINES = -DGET_TGT_VIA_PASSWD -DPRINC_LOOK_AHEAD -DCMD_PATH='"/bin /local/bin"'
+DEFINES = -DGET_TGT_VIA_PASSWD -DPRINC_LOOK_AHEAD -DCMD_PATH='"/usr/local/sbin /usr/local/bin /sbin /usr/sbin /bin /usr/bin"'
DEFS=
PROG_LIBPATH=-L$(TOPLIBD)