add configure script for pgsql server libs

This used to be in osm2pgsql but now has magically disappeared.

configure.ac

@@ -9,6 +9,7 @@ AC_PREREQ(2.61)
 AM_INIT_AUTOMAKE([1.9.6 dist-bzip2 std-options check-news])
 
 dnl Additional macro definitions are in here
+m4_include([m4/ax_lib_postgresql_svr.m4])
 AC_CONFIG_MACRO_DIR([osm2pgsql/m4])
 
 dnl Generate configuration header file
@@ -45,6 +46,7 @@ if test "x$POSTGRESQL_VERSION" = "x"
 then
     AC_MSG_ERROR([postgresql client library not found])
 fi
+AX_LIB_POSTGRESQL_SVR(9.0)
 if test ! -f "$POSTGRESQL_PGXS"
 then
     AC_MSG_ERROR([postgresql server development library not found])

m4/ax_lib_postgresql_svr.m4

@@ -0,0 +1,125 @@
+# SYNOPSIS
+#
+#   AX_LIB_POSTGRESQL_SVR([MINIMUM-VERSION])
+#
+# DESCRIPTION
+#
+#   This macro provides tests of availability of PostgreSQL server library
+#
+#   This macro calls:
+#
+#     AC_SUBST(POSTGRESQL_PGXS)
+#     AC_SUBST(POSTGRESQL_SERVER_CFLAGS)
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Mateusz Loskot <mateusz@loskot.net>
+#   Copyright (c) 2015 Sarah Hoffmann <lonia@denofr.de>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved.
+
+AC_DEFUN([AX_LIB_POSTGRESQL_SVR],
+[
+    AC_ARG_WITH([postgresql],
+        AC_HELP_STRING([--with-postgresql-svr=@<:@ARG@:>@],
+            [use PostgreSQL server library @<:@default=yes@:>@, optionally specify path to pg_config]
+        ),
+        [
+        if test "$withval" = "no"; then
+            want_postgresql="no"
+        elif test "$withval" = "yes"; then
+            want_postgresql="yes"
+        else
+            want_postgresql="yes"
+            PG_CONFIG="$withval"
+        fi
+        ],
+        [want_postgresql="yes"]
+    )
+
+    dnl
+    dnl Check PostgreSQL server libraries
+    dnl
+
+    if test "$want_postgresql" = "yes"; then
+
+        if test -z "$PG_CONFIG" -o test; then
+            AC_PATH_PROG([PG_CONFIG], [pg_config], [])
+        fi
+
+        if test ! -x "$PG_CONFIG"; then
+            AC_MSG_ERROR([$PG_CONFIG does not exist or it is not an exectuable file])
+            PG_CONFIG="no"
+            found_postgresql="no"
+        fi
+
+        if test "$PG_CONFIG" != "no"; then
+            AC_MSG_CHECKING([for PostgreSQL server libraries])
+
+            POSTGRESQL_SERVER_CFLAGS="-I`$PG_CONFIG --includedir-server`"
+
+            POSTGRESQL_VERSION=`$PG_CONFIG --version | sed -e 's#PostgreSQL ##'`
+
+            POSTGRESQL_PGXS=`$PG_CONFIG --pgxs`
+        if test -f "$POSTGRESQL_PGXS"
+        then
+          found_postgresql="yes"
+              AC_MSG_RESULT([yes])
+        fi
+        else
+            found_postgresql="no"
+            AC_MSG_RESULT([no])
+        fi
+    fi
+
+    dnl
+    dnl Check if required version of PostgreSQL is available
+    dnl
+
+
+    postgresql_version_req=ifelse([$1], [], [], [$1])
+
+    if test "$found_postgresql" = "yes" -a -n "$postgresql_version_req"; then
+
+        AC_MSG_CHECKING([if PostgreSQL version is >= $postgresql_version_req])
+
+        dnl Decompose required version string of PostgreSQL
+        dnl and calculate its number representation
+        postgresql_version_req_major=`expr $postgresql_version_req : '\([[0-9]]*\)'`
+        postgresql_version_req_minor=`expr $postgresql_version_req : '[[0-9]]*\.\([[0-9]]*\)'`
+        postgresql_version_req_micro=`expr $postgresql_version_req : '[[0-9]]*\.[[0-9]]*\.\([[0-9]]*\)'`
+        if test "x$postgresql_version_req_micro" = "x"; then
+            postgresql_version_req_micro="0"
+        fi
+
+        postgresql_version_req_number=`expr $postgresql_version_req_major \* 1000000 \
+                                   \+ $postgresql_version_req_minor \* 1000 \
+                                   \+ $postgresql_version_req_micro`
+
+        dnl Decompose version string of installed PostgreSQL
+        dnl and calculate its number representation
+        postgresql_version_major=`expr $POSTGRESQL_VERSION : '\([[0-9]]*\)'`
+        postgresql_version_minor=`expr $POSTGRESQL_VERSION : '[[0-9]]*\.\([[0-9]]*\)'`
+        postgresql_version_micro=`expr $POSTGRESQL_VERSION : '[[0-9]]*\.[[0-9]]*\.\([[0-9]]*\)'`
+        if test "x$postgresql_version_micro" = "x"; then
+            postgresql_version_micro="0"
+        fi
+
+        postgresql_version_number=`expr $postgresql_version_major \* 1000000 \
+                                   \+ $postgresql_version_minor \* 1000 \
+                                   \+ $postgresql_version_micro`
+
+        postgresql_version_check=`expr $postgresql_version_number \>\= $postgresql_version_req_number`
+        if test "$postgresql_version_check" = "1"; then
+            AC_MSG_RESULT([yes])
+        else
+            AC_MSG_RESULT([no])
+        fi
+    fi
+
+    AC_SUBST([POSTGRESQL_PGXS])
+    AC_SUBST([POSTGRESQL_SERVER_CFLAGS])
+])
+