procps-ng: fix BR2_STATIC_LIBS=y build

The procps-ng package currently fails to build on BR2_STATIC_LIBS=y
configurations. Indeed, by default NUMA support is enabled, and it
requires dlopen(). As hinted by the configure script, passing
--disable-numa allows to disable NUMA support.

However, once this is done, another issue pops up: dlopen() is also used
by the SELinux support. But even when SELinux support is disabled, the
procps-ng code incorrectly includes <dlfcn.h>. This is addressed by the
addition of a patch.

Fixes:

  http://autobuild.buildroot.net/results/b385bf435085728aece6323a5006ba9fa6631744/

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

package/procps-ng/0003-ps-output.c-include-dlfcn.h-only-when-necessary.patch

@@ -0,0 +1,32 @@
+From 4fc9a348026a945aec8eddffc7613de9cb10b10c Mon Sep 17 00:00:00 2001
+From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+Date: Sun, 7 Aug 2016 11:08:26 +0200
+Subject: [PATCH] ps/output.c: include <dlfcn.h> only when necessary
+
+dlopen() functionality is only used when SELinux support is enabled, so
+<dlfcn.h> only needs to be included when ENABLE_LIBSELINUX is
+defined. This fixes the build in configurations where <dlfcn.h> is not
+available.
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+---
+ ps/output.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/ps/output.c b/ps/output.c
+index 42c04cf..f540832 100644
+--- a/ps/output.c
++++ b/ps/output.c
+@@ -46,7 +46,9 @@
+  */
+ 
+ #include <ctype.h>
++#if ENABLE_LIBSELINUX
+ #include <dlfcn.h>
++#endif
+ #include <fcntl.h>
+ #include <grp.h>
+ #include <limits.h>
+-- 
+2.7.4
+

package/procps-ng/procps-ng.mk

@@ -47,4 +47,10 @@ PROCPS_NG_CONF_OPTS += \
 	--enable-watch8bit
 endif
 
+# numa support requires libdl, so explicitly disable it when
+# BR2_STATIC_LIBS=y
+ifeq ($(BR2_STATIC_LIBS),y)
+PROCPS_NG_CONF_OPTS += --disable-numa
+endif
+
 $(eval $(autotools-package))