procps-ng: add required build dependencies

Since 3048ebe added a autoreconfig fixup to
procps-ng, the build fails on certain systems with errors like

    configure.ac:72: error: possibly undefined macro: AM_GNU_GETTEXT_VERSION

or

    configure:14998: error: possibly undefined macro: AM_ICONV_LINKFLAGS_BODY

Fix the issue by adding build time dependencies on the `gettext` and `libiconv`
stub libraries to ensure that `gettext.m4` and `iconv.m4` are installed into
the staging directory before `procps-ng` is getting reconfigured.

Fixes openwrt#2890 (comment)

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

utils/procps-ng/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=procps-ng
 PKG_VERSION:=3.3.11
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 PKG_LICENSE:=GPL-2.0
 PKG_LICENSE_FILES:=COPYING COPYING.LIB
 
@@ -22,6 +22,7 @@ PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-$(PKG_SOURCE_VERSION).tar.gz
 PKG_BUILD_PARALLEL:=1
 PKG_INSTALL:=1
 PKG_FIXUP:=autoreconf
+PKG_BUILD_DEPENDS:=gettext libiconv
 
 include $(INCLUDE_DIR)/package.mk