Upgrade socat to 1.7.3.0.

The cross-compiling patch is no longer necessary.  Also added librt as a
dependency, since it is required.  This also fixes an issue where
support for linux/errqueue.h was not being detected correctly and
causing a build failure with 3.18.

Signed-off-by: John Szakmeister <john@szakmeister.net>

net/socat/Makefile

@@ -8,12 +8,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=socat
-PKG_VERSION:=1.7.2.4
-PKG_RELEASE:=2
+PKG_VERSION:=1.7.3.0
+PKG_RELEASE:=1
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=http://www.dest-unreach.org/socat/download
-PKG_MD5SUM:=69b8155dd442a6f24e28ef5407d868eb
+PKG_MD5SUM:=b607edb65bc6c57f4a43f06247504274
 
 PKG_MAINTAINER:= Ted Hess <thess@kitschensync.net>
 
@@ -27,7 +27,7 @@ include $(INCLUDE_DIR)/package.mk
 define Package/socat
   SECTION:=net
   CATEGORY:=Network
-  DEPENDS:=+libpthread +SOCAT_SSL:libopenssl
+  DEPENDS:=+libpthread +librt +SOCAT_SSL:libopenssl
   TITLE:=A multipurpose relay (SOcket CAT)
   URL:=http://www.dest-unreach.org/socat/
 endef

net/socat/patches/010-fix_cross_compiling_error.patch

@@ -1,22 +0,0 @@
---- a/configure.in
-+++ b/configure.in
-@@ -41,7 +41,7 @@ AC_CHECK_PROG(AR, ar, ar, gar)
- # fail
- AC_LANG_COMPILER_REQUIRE()
- 
--if test "$CC" = "gcc"; then
-+if test "$GCC" = yes; then
-    CFLAGS="$CFLAGS -D_GNU_SOURCE -Wall -Wno-parentheses"
-    ERRONWARN="-Werror -O0"
- elif test "$CC" = "clang"; then
---- a/configure
-+++ b/configure
-@@ -3348,7 +3348,7 @@ fi
- 
- 
- 
--if test "$CC" = "gcc"; then
-+if test "$GCC" = yes; then
-    CFLAGS="$CFLAGS -D_GNU_SOURCE -Wall -Wno-parentheses"
-    ERRONWARN="-Werror -O0"
- elif test "$CC" = "clang"; then