libpqxx: apply upstream compilation fix

Apply an upstream patch which addresses a compilation issue with respect
to an undefined 'timeval' structure. This issue exists in at least v6.0.
It is expected that this patch can be removed when libpqxx provides a
new releases (either v6.0.1 or v6.1).

Fixes:
http://autobuild.buildroot.net/results/48b015650ede4e55e199538072c7228cccf64422

Signed-off-by: James Knight <james.knight@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libpqxx/0001-include-sys-time.h-outside-fallback-select-55.patch

@@ -0,0 +1,119 @@
+From 44970d7331e4f369e160af0135a2d1fc16f27a21 Mon Sep 17 00:00:00 2001
+From: jdknight-rockwellcollins <james.knight@rockwellcollins.com>
+Date: Mon, 15 Jan 2018 12:41:25 -0500
+Subject: [PATCH] include sys/time.h outside fallback select (#55)
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+The implementation of 'wait_fd' (inside 'connection_base.cxx') always
+relies on the existence of the 'timeval' structure. In Linux, this
+structure is provided by the header 'sys/time.h'. If polling or select
+capabilities are detected, the structure is never included into the
+source and will result in a compilation error (GCC 7.x):
+
+    connection_base.cxx:1153:28: error: ‘{anonymous}::tv_milliseconds’ declared as an ‘inline’ variable
+     inline int tv_milliseconds(timeval *tv = nullptr)
+                                ^~~~~~~
+    ...
+
+The following moves the 'HAVE_SYS_TIME_H' check outside the
+select-fallback case so that the header can be included no matter the
+event-function feature is used.
+
+Signed-off-by: James Knight <james.knight@rockwellcollins.com>
+---
+ configure               | 28 ++++++++++++----------------
+ configure.ac            |  6 +-----
+ src/connection_base.cxx |  2 +-
+ 3 files changed, 14 insertions(+), 22 deletions(-)
+
+diff --git a/configure b/configure
+index 7d6d96a98e0fcb7dde1e05adf034afe624ada6d6..dd2a33cb54dba5d3223fc2b4c8d03be7c8abde4e 100755
+--- a/configure
++++ b/configure
+@@ -17285,22 +17285,6 @@ fi
+ done
+ 
+ 
+-if test "$select_h" != "yes"
+-then
+-for ac_header in sys/time.h
+-do :
+-  ac_fn_cxx_check_header_mongrel "$LINENO" "sys/time.h" "ac_cv_header_sys_time_h" "$ac_includes_default"
+-if test "x$ac_cv_header_sys_time_h" = xyes; then :
+-  cat >>confdefs.h <<_ACEOF
+-#define HAVE_SYS_TIME_H 1
+-_ACEOF
+-
+-fi
+-
+-done
+-
+-fi
+-
+ # Some systems keep select() in a separate library which is not linked by
+ # default.  See if we need one of those.
+ socklibok=no
+@@ -17419,6 +17403,18 @@ fi
+ 
+ fi # No poll()
+ 
++for ac_header in sys/time.h
++do :
++  ac_fn_cxx_check_header_mongrel "$LINENO" "sys/time.h" "ac_cv_header_sys_time_h" "$ac_includes_default"
++if test "x$ac_cv_header_sys_time_h" = xyes; then :
++  cat >>confdefs.h <<_ACEOF
++#define HAVE_SYS_TIME_H 1
++_ACEOF
++
++fi
++
++done
++
+ 
+ # Add options to compiler command line, if compiler accepts them.
+ add_compiler_opts_if_ok() {
+diff --git a/configure.ac b/configure.ac
+index 8977c3d3900a5de66b580365d8fe7d133cd1042d..6649f7fa0ed0572489a0db09517c659012ce707c 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -117,11 +117,6 @@ then
+ select_h=no
+ AC_CHECK_HEADERS([sys/select.h], [select_h=yes])
+ 
+-if test "$select_h" != "yes"
+-then
+-AC_CHECK_HEADERS([sys/time.h])
+-fi
+-
+ # Some systems keep select() in a separate library which is not linked by
+ # default.  See if we need one of those.
+ socklibok=no
+@@ -150,6 +145,7 @@ fi
+ 
+ fi # No poll()
+ 
++AC_CHECK_HEADERS([sys/time.h])
+ 
+ # Add options to compiler command line, if compiler accepts them.
+ add_compiler_opts_if_ok() {
+diff --git a/src/connection_base.cxx b/src/connection_base.cxx
+index 37ed7728ffd02e1fded3b5d64d6fb2d5fd74d5ed..0ec55bc5bd761690f66b67396cfbf3e3c56ba618 100644
+--- a/src/connection_base.cxx
++++ b/src/connection_base.cxx
+@@ -38,10 +38,10 @@
+ #if defined(HAVE_UNISTD_H)
+ #include <unistd.h>
+ #endif
++#endif
+ #if defined(HAVE_SYS_TIME_H)
+ #include <sys/time.h>
+ #endif
+-#endif
+ 
+ #include "libpq-fe.h"
+ 
+-- 
+1.8.3.msysgit.0
+