rng-tools: fix the build with musl

musl doesn't provide argp, so we need argp-standalone, as we do for uclibc.
Rather than passing in -largp via the recipe, patch the configure script to
provide an argument for the libargp usage and check for it when needed, and
use PACKAGECONFIG. The initial patch to check for libargp and use it if
available came from Gentoo. The patches are kept separate despite the second
modifying what the first does, in order to keep the history/origin clear.

(From OE-Core rev: 94ecc846f9b33fcec039936643c49728eedfefb7)

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 92 insertions, 0 deletions

diff --git a/meta/recipes-support/rng-tools/rng-tools/0002-Add-argument-to-control-the-libargp-dependency.patch b/meta/recipes-support/rng-tools/rng-tools/0002-Add-argument-to-control-the-libargp-dependency.patch
new file mode 100644
index 0000000000..1c8a79ce0b
--- /dev/null
+++ b/meta/recipes-support/rng-tools/rng-tools/0002-Add-argument-to-control-the-libargp-dependency.patch
@@ -0,0 +1,92 @@
+From afc8712a9e6c72fbd03c36f84ecf8703e5d22a8c Mon Sep 17 00:00:00 2001
+From: Christopher Larson <chris_larson@mentor.com>
+Date: Mon, 15 Feb 2016 16:11:32 -0700
+Subject: [PATCH 2/2] Add argument to control the libargp dependency
+
+This ensures that the builds are always deterministic. If the argument isn't
+passed, the default behavior is to use libargp if the libc doesn't have argp.
+
+Upstream-Status: Pending
+Signed-off-by: Christopher Larson <chris_larson@mentor.com>
+---
+ configure.ac | 55 ++++++++++++++++++++++++++++++++++++-------------------
+ 1 file changed, 36 insertions(+), 19 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index 04fcd25..11a5321 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -32,6 +32,13 @@ AC_ARG_WITH([libgcrypt],
+        [with_libgcrypt=check]
+ )
+ 
++AC_ARG_WITH([libargp],
++       AS_HELP_STRING([--without-libargp],
++               [Disable libargp support. Systems whose libc lacks argp can use libargp instead. (Default: check if libc lacks argp)]),
++       [with_libargp=$withval],
++       [with_libargp=check]
++)
++
+ dnl Make sure anyone changing configure.ac/Makefile.am has a clue
+ AM_MAINTAINER_MODE
+ 
+@@ -82,27 +89,37 @@ AS_IF(
+        ]
+ )
+ 
+-dnl First check if we have argp available from libc
+-AC_LINK_IFELSE(
+-       [AC_LANG_PROGRAM(
+-               [#include <argp.h>],
+-               [int argc=1; char *argv[]={"test"}; argp_parse(0,argc,argv,0,0,0); return 0;]
+-               )],
+-       [libc_has_argp="true"],
+-       [libc_has_argp="false"]
++dnl Determine if we need libargp: either user requested, or libc has no argp
++AS_IF(
++       [test "x$with_libargp" != "xyes"],
++       [
++               AC_LINK_IFELSE(
++                       [AC_LANG_PROGRAM(
++                               [#include <argp.h>],
++                               [int argc=1; char *argv[]={"test"}; argp_parse(0,argc,argv,0,0,0); return 0;]
++                               )],
++                       [need_libargp=no],
++                       [need_libargp=yes
++                        if test "x$with_libargp" = "xno"; then
++                               AC_MSG_FAILURE([libargp disabled and libc does not have argp])
++                        fi]
++               )
++       ],
++       [need_libargp=yes],
+ )
+ 
+-dnl If libc doesn't provide argp, then test for libargp
+-if test "$libc_has_argp" = "false" ; then
+-       AC_MSG_WARN("libc does not have argp")
+-       AC_CHECK_LIB([argp], [argp_parse], [have_argp="true"], [have_argp="false"])
+-
+-       if test "$have_argp" = "false"; then
+-               AC_MSG_ERROR("no libargp found")
+-       else
+-               LIBS+=" -largp"
+-       fi
+-fi
++dnl Check for libargp
++AS_IF(
++       [test "x$need_libargp" = "xyes"],
++       [
++               AC_CHECK_LIB(
++                       [argp],
++                       [argp_parse],
++                       [LIBS="$LIBS -largp"],
++                       [AC_MSG_FAILURE([libargp not found])]
++               )
++       ]
++)
+ 
+ dnl -----------------
+ dnl Configure options
+-- 
+2.2.1
+