File avoid-pg-config.patch of Package collectd

diff --git a/configure.ac b/configure.ac
index 4032d84..284192d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4272,18 +4272,10 @@ AC_SUBST([PERL_LIBS])
 # }}}
 
 # --with-libpq {{{
-with_pg_config="pg_config"
 AC_ARG_WITH([libpq],
-  [AS_HELP_STRING([--with-libpq@<:@=PREFIX@:>@], [Path to libpq.])],
+  [AS_HELP_STRING([--with-libpq], [Build using pgsql])],
   [
-    if test "x$withval" = "xno" || test "x$withval" = "xyes"; then
-      with_libpq="$withval"
-    else
-      if test -f "$withval" && test -x "$withval"; then
-        with_pg_config="$withval"
-      else if test -x "$withval/bin/pg_config"; then
-        with_pg_config="$withval/bin/pg_config"
-      fi; fi
+    if test "x$withval" != "xno" || test "x$withval" != "xyes"; then
       with_libpq="yes"
     fi
   ],
@@ -4291,66 +4283,42 @@ AC_ARG_WITH([libpq],
 )
 
 if test "x$with_libpq" = "xyes"; then
-  with_libpq_includedir=`$with_pg_config --includedir 2> /dev/null`
-  pg_config_status=$?
-
-  if test $pg_config_status -eq 0; then
-    if test -n "$with_libpq_includedir"; then
-      for dir in $with_libpq_includedir; do
-        with_libpq_cppflags="$with_libpq_cppflags -I$dir"
-      done
-    fi
-  else
-    AC_MSG_WARN([$with_pg_config returned with status $pg_config_status])
+  $PKG_CONFIG --exists 'libpq' 2>/dev/null
+  if test $? -ne 0; then
+    with_libpq="no (pkg-config doesn't know libpq)"
   fi
-
-  SAVE_CPPFLAGS="$CPPFLAGS"
-  CPPFLAGS="$CPPFLAGS $with_libpq_cppflags"
-
-  AC_CHECK_HEADERS([libpq-fe.h],
-    [with_libpq="yes"],
-    [with_libpq="no (libpq-fe.h not found)"]
-  )
-
-  CPPFLAGS="$SAVE_CPPFLAGS"
 fi
 
 if test "x$with_libpq" = "xyes"; then
-  with_libpq_libdir=`$with_pg_config --libdir 2> /dev/null`
-  pg_config_status=$?
-
-  if test $pg_config_status -eq 0
-  then
-    if test -n "$with_libpq_libdir"; then
-      for dir in $with_libpq_libdir; do
-        with_libpq_ldflags="$with_libpq_ldflags -L$dir"
-      done
-    fi
-  else
-    AC_MSG_WARN([$with_pg_config returned with status $pg_config_status])
-  fi
+  with_libpq_cflags="`$PKG_CONFIG --cflags libpq`"
+  with_libpq_ldflags="`$PKG_CONFIG --libs-only-L libpq`"
+  with_libpq_libs="`$PKG_CONFIG --libs libpq`"
+fi
 
-  SAVE_LDFLAGS="$LDFLAGS"
-  LDFLAGS="$LDFLAGS $with_libpq_ldflags"
+if test "x$with_libpq" = "xyes"; then
+  SAVE_CPPFLAGS="$CPPFLAGS"
+  CPPFLAGS="$CPPFLAGS $with_libpq_cflags"
 
-  AC_CHECK_LIB([pq], [PQserverVersion],
-    [with_libpq="yes"],
-    [with_libpq="no (symbol 'PQserverVersion' not found)"])
+  # Look for libpq-fe.h
+  AC_CHECK_HEADERS([libpq-fe.h pgsql/libpq-fe.h],
+  [with_libpq="yes"],
+  [with_libpq="no (libpq-fe.h not found)"]
+  )
 
-  LDFLAGS="$SAVE_LDFLAGS"
+  CPPFLAGS="$SAVE_CPPFLAGS"
 fi
 
 if test "x$with_libpq" = "xyes"; then
-  BUILD_WITH_LIBPQ_CPPFLAGS="$with_libpq_cppflags"
+  BUILD_WITH_LIBPQ_CPPFLAGS="$with_libpq_cflags"
   BUILD_WITH_LIBPQ_LDFLAGS="$with_libpq_ldflags"
-  BUILD_WITH_LIBPQ_LIBS="-lpq"
+  BUILD_WITH_LIBPQ_LIBS="$with_libpq_libs"
 fi
 
 AC_SUBST([BUILD_WITH_LIBPQ_CPPFLAGS])
-AC_SUBST([BUILD_WITH_LIBPQ_LDFLAGS])
 AC_SUBST([BUILD_WITH_LIBPQ_LIBS])
 # }}}
 
+
 # --with-libpqos {{{
 AC_ARG_WITH([libpqos],
   [AS_HELP_STRING([--with-libpqos@<:@=PREFIX@:>@], [Path to libpqos.])],