util-linux: linux-pam is needed for runuser

With linux-pam, the configure script bails out with:

configure: error: runuser selected, but required PAM header file not available

Fixes:

  http://autobuild.buildroot.net/results/ea7430012f1d8e2ae3ceb8fe5d41630ea1eaa3af/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/util-linux/Config.in

@@ -297,12 +297,20 @@ config BR2_PACKAGE_UTIL_LINUX_RESET
 
 config BR2_PACKAGE_UTIL_LINUX_RUNUSER
 	bool "runuser"
-	depends on BR2_USE_MMU # fork()
+	depends on (BR2_ENABLE_LOCALE && BR2_USE_WCHAR) # linux-pam
+	depends on !BR2_STATIC_LIBS
+	depends on !BR2_TOOLCHAIN_USES_MUSL # linux-pam
+	depends on BR2_USE_MMU # fork(), linux-pam
+	select BR2_PACKAGE_LINUX_PAM
 	help
 	  Run a command with substitute user and group ID (does not need
 	  to ask for a password, because it may be executed by the root
 	  user only)
 
+comment "runuser needs a uClibc or glibc toolchain w/ wchar, locale, dynamic library"
+	depends on !(BR2_ENABLE_LOCALE && BR2_USE_WCHAR) \
+		|| BR2_STATIC_LIBS || BR2_TOOLCHAIN_USES_MUSL
+
 config BR2_PACKAGE_UTIL_LINUX_SCHEDUTILS
 	bool "scheduling utilities"
 	help