configure: Add --with-pam-dir option for configurable PAM directory

The PAM configuration directory was hardcoded to /etc/pam.d (or
/usr/local/etc/pam.d on FreeBSD), which prevented non-root installations.

This change:
- Adds --with-pam-dir configure option to specify PAM config location
- Defaults to /etc/pam.d for system installs (prefix=/usr or /usr/local)
- Defaults to PREFIX/etc/pam.d for local/user installs
- Updates dtlogin/config/Makefile.am to use the PAM_CONFDIR variable

Examples:
  # User installation (PAM config goes to ~/cde/etc/pam.d)
  ./configure --prefix=$HOME/cde

  # System install with standard PAM location
  ./configure --prefix=/usr  # PAM goes to /etc/pam.d

  # Explicit PAM directory
  ./configure --prefix=/opt/cde --with-pam-dir=/etc/pam.d

cde/configure.ac

@@ -550,11 +550,25 @@ AM_ICONV
 
 dnl figure out pam support
 dnl Right now this only works on linux and netbsd (9.2 tested)
+
+dnl PAM configuration directory - configurable for non-root installs
+AC_ARG_WITH([pam-dir],
+  AS_HELP_STRING([--with-pam-dir=DIR],
+    [directory for PAM configuration files (default: /etc/pam.d, or PREFIX/etc/pam.d if prefix is not /usr)]),
+  [PAM_CONFDIR="$withval"],
+  [if test "x$cde_prefix" = "x/usr" -o "x$cde_prefix" = "x/usr/local"; then
+     PAM_CONFDIR="/etc/pam.d"
+   else
+     PAM_CONFDIR="${cde_prefix}/etc/pam.d"
+   fi])
+AC_SUBST(PAM_CONFDIR)
+
 if test "$supports_pam" = "yes"
 then
         AC_CHECK_LIB(pam, pam_start,
              [SOURCE_CPP_DEFINES="${SOURCE_CPP_DEFINES} -DHAS_PAM_LIBRARY";
-	      PAMLIB="-lpam"])
+	      PAMLIB="-lpam";
+              AC_MSG_NOTICE([PAM configuration directory: $PAM_CONFDIR])])
         AC_SUBST(PAMLIB)
 else
         AC_CHECK_LIB(pam, NOTSUPPORTED)

cde/programs/dtlogin/config/Makefile.am

@@ -18,18 +18,16 @@ CPP_TARGETS = 0060.dtsysenv Dtlogin Xaccess Xconfig Xconfig.con	\
 if HAS_PAM_LIBRARY
 CPP_TARGETS += dtlogin
 dist_pam_DATA = dtlogin
+pamdir = $(PAM_CONFDIR)
 if FREEBSD
-pamdir = /usr/local/etc/pam.d
 PAM_AUTHENTICATION_MODULE = /usr/local/lib/security/pam_pwauth_suid.so
 AM_CPPFLAGS += -DPAM_AUTHENTICATION_MODULE=$(PAM_AUTHENTICATION_MODULE)
-else
-pamdir = /etc/pam.d
+endif
 if NETBSD
 PAM_AUTHENTICATION_MODULE = /usr/pkg/lib/security/pam_pwauth_suid.so
 AM_CPPFLAGS += -DPAM_AUTHENTICATION_MODULE=$(PAM_AUTHENTICATION_MODULE)
 endif
 endif
-endif
 
 if LINUX
 AM_CPPFLAGS += -DXPROJECTROOT="/usr" -Dlinux -D__linux__