lxdm: Find libexecinfo if its on platform

fixes build with musl

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-graphics/lxdm/lxdm/0001-check-for-libexecinfo-providing-backtrace-APIs.patch

@@ -0,0 +1,36 @@
+From 1d2425febf2020e38db70188df582acc9f37b136 Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Thu, 30 Mar 2017 13:01:33 -0700
+Subject: [PATCH] check for libexecinfo providing backtrace() APIs
+
+on musl it depends on external library to provide backtrace APIs
+unlike glibc where it is bundled in
+
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ configure.ac | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/configure.ac b/configure.ac
+index aa3291c..b15f65d 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -15,6 +15,7 @@ AM_PROG_CC_C_O
+ 
+ # Checks for libraries.
+ AC_CHECK_LIB([crypt], [crypt])
++AC_CHECK_LIB([execinfo], [backtrace])
+ 
+ # Check for PAM support
+ AC_ARG_WITH(pam, AC_HELP_STRING([--with-pam],[Use PAM for authentication]),
+@@ -33,6 +34,7 @@ AM_CONDITIONAL(HAVE_PAM, [test -n "$USE_PAM" -a "x$USE_PAM" != xno ])
+ # Checks for header files.
+ AC_PATH_X
+ AC_CHECK_HEADERS([shadow.h stdlib.h string.h unistd.h utmpx.h])
++AC_CHECK_HEADERS([execinfo.h])
+ 
+ # Checks for typedefs, structures, and compiler characteristics.
+ AC_TYPE_PID_T
+-- 
+2.12.1
+

meta-oe/recipes-graphics/lxdm/lxdm_0.5.3.bb

@@ -2,13 +2,13 @@ SUMMARY = "LXDM is the lightweight display manager"
 HOMEPAGE = "http://blog.lxde.org/?p=531"
 LICENSE = "GPLv3"
 LIC_FILES_CHKSUM = "file://COPYING;md5=d32239bcb673463ab874e80d47fae504"
-SRC_URI = " \
+SRC_URI = "${SOURCEFORGE_MIRROR}/project/${BPN}/${BPN}%20${PV}/${BPN}-${PV}.tar.xz \
-    ${SOURCEFORGE_MIRROR}/project/${BPN}/${BPN}%20${PV}/${BPN}-${PV}.tar.xz \
+           file://lxdm.conf \
-    file://lxdm.conf \
+           ${@bb.utils.contains('DISTRO_FEATURES', 'pam', 'file://lxdm-pam file://lxdm-pam-debug', '', d)} \
-    ${@bb.utils.contains('DISTRO_FEATURES', 'pam', 'file://lxdm-pam file://lxdm-pam-debug', '', d)} \
+           ${@bb.utils.contains("DISTRO_TYPE", "debug", "", "file://0001-lxdm.conf.in-blacklist-root-for-release-images.patch",d)} \
-    ${@bb.utils.contains("DISTRO_TYPE", "debug", "", "file://0001-lxdm.conf.in-blacklist-root-for-release-images.patch",d)} \
+           file://0002-let-autotools-create-lxdm.conf.patch \
-    file://0002-let-autotools-create-lxdm.conf.patch \
+           file://0001-check-for-libexecinfo-providing-backtrace-APIs.patch \
-"
+           "
 SRC_URI[md5sum] = "061caae432634e6db38bbdc84bc6ffa0"
 SRC_URI[sha256sum] = "4891efee81c72a400cc6703e40aa76f3f3853833d048b72ec805da0f93567f2f"
 
@@ -16,6 +16,7 @@ PE = "1"
 
 DEPENDS = "virtual/libintl intltool-native cairo dbus gdk-pixbuf glib-2.0 gtk+ virtual/libx11 libxcb pango iso-codes"
 DEPENDS += "${@bb.utils.contains("DISTRO_FEATURES", "systemd", "", "consolekit", d)}"
+DEPENDS_append_libc-musl = " libexecinfo"
 
 # combine oe-core way with angstrom DISTRO_TYPE
 DISTRO_TYPE ?= "${@bb.utils.contains("IMAGE_FEATURES", "debug-tweaks", "debug", "",d)}"
@@ -25,6 +26,7 @@ inherit autotools pkgconfig gettext systemd distro_features_check
 REQUIRED_DISTRO_FEATURES = "x11"
 
 CFLAGS_append = " -fno-builtin-fork -fno-builtin-memset -fno-builtin-strstr "
+LDFLAGS_append_libc-musl = " -lexecinfo"
 
 EXTRA_OECONF += "--enable-gtk3=no --enable-password=yes --with-x -with-xconn=xcb \
     ${@bb.utils.contains('DISTRO_FEATURES', 'systemd', '--with-systemdsystemunitdir=${systemd_unitdir}/system/ --disable-consolekit', '--without-systemdsystemunitdir', d)} \