Fix problem with PPASSFILE having the literal '${prefix}' prefix

configure.ac

@@ -3,6 +3,7 @@ AC_CONFIG_AUX_DIR([build-aux])
 AM_INIT_AUTOMAKE([-Wall])
 AC_PREREQ([2.69])
 AC_CONFIG_MACRO_DIR([m4])
+AC_CONFIG_HEADER([src/config.h])
 AC_CANONICAL_HOST
 
 AC_SUBST(PACKAGE)
@@ -13,23 +14,27 @@ AC_PROG_CC
 AM_PROG_AR
 
 AC_PATH_PROG([REBOOT], [reboot])
-AC_SUBST(REBOOT)
+AC_DEFINE_UNQUOTED([REBOOT], "$REBOOT",
+    [path to the reboot command])
 AC_PATH_PROG([POWEROFF], [poweroff])
-AC_SUBST(POWEROFF)
+AC_DEFINE_UNQUOTED([POWEROFF], "$POWEROFF",
+    [path to the poweroff command])
 AC_PATH_PROG([CRYPTSETUP], [cryptsetup])
-AC_SUBST(CRYPTSETUP)
+AC_DEFINE_UNQUOTED([CRYPTSETUP], "$CRYPTSETUP",
+    [path to the cryptsetup command])
 
 AC_ARG_ENABLE(securedir,
     AS_HELP_STRING([--enable-securedir=DIR],
-        [path to location of PAMs @<:@default=$libdir/security@:>@]),
+        [path to location of PAMs @<:@default=LIBDIR/security@:>@]),
     SECUREDIR=$enableval, SECUREDIR=$libdir/security)
 AC_SUBST(SECUREDIR)
 
 AC_ARG_ENABLE(ppassfile,
     AS_HELP_STRING([--enable-ppassfile=FILE],
-        [path to file to be used for storing passwords @<:@default=$sysconfdir/pam_panic/auth@:>@]),
-    PPASSFILE=$enableval, PPASSFILE=$sysconfdir/pam_panic/auth)
-AC_SUBST(PPASSFILE)
+        [path to file to be used for storing passwords @<:@default=/etc/pam_panic/auth@:>@]),
+    PPASSFILE=$enableval, PPASSFILE=/var/lib/pam_panic/auth)
+AC_DEFINE_UNQUOTED([PPASSFILE], "$PPASSFILE",
+    [path to file to be used for storing passwords])
 
 LT_INIT([disable-static])
 AC_ENABLE_STATIC([no])
@@ -37,10 +42,8 @@ AC_ENABLE_SHARED([yes])
 
 AC_CONFIG_FILES([
     Makefile
-    src/pam_panic/config.h
     src/pam_panic/Makefile
     src/pam_panic/man/Makefile
-    src/pam_panic_pw/config.h
     src/pam_panic_pw/Makefile
     src/pam_panic_pw/man/Makefile
 ])