Add support for Oracle 12: do not try to link to nnz10 but to nnz12

m4/ax_lib_oracle_oci.m4

@@ -41,13 +41,14 @@
 # LICENSE
 #
 #   Copyright (c) 2008 Mateusz Loskot <mateusz@loskot.net>
+#   Copyright (c) 2015 Joost van Baal-Ilić <joostvb+autoconf@uvt.nl>
 #
 #   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. This file is offered as-is, without any
 #   warranty.
 
-#serial 10
+#serial 11
 
 AC_DEFUN([AX_LIB_ORACLE_OCI],
 [
@@ -271,15 +272,25 @@ if (envh) OCIHandleFree(envh, OCI_HTYPE_ENV);
                 oracle_version_checked="yes"
                 AC_MSG_RESULT([yes])
 
-                dnl Add -lnnz10 flag to Oracle >= 10.x
-                AC_MSG_CHECKING([for Oracle version >= 10.x to use -lnnz10 flag])
-                oracle_nnz10_check=`expr $oracle_version_number \>\= 10 \* 1000000`
-                if test "$oracle_nnz10_check" = "1"; then
+                dnl Add -lnnz10 flag to Oracle = 10.x
+                AC_MSG_CHECKING([for Oracle version = 10.x to use -lnnz10 flag])
+                oracle_nnz_check=`expr $oracle_version_major \= 10`
+                if test "$oracle_nnz_check" = "1"; then
                     ORACLE_OCI_LDFLAGS="$ORACLE_OCI_LDFLAGS -lnnz10"
                     AC_MSG_RESULT([yes])
                 else
                     AC_MSG_RESULT([no])
                 fi
+
+                dnl Add -lnnz12 flag to Oracle = 12.x
+                AC_MSG_CHECKING([for Oracle version = 12.x to use -lnnz12 flag])
+                oracle_nnz_check=`expr $oracle_version_major \= 12`
+                if test "$oracle_nnz_check" = "1"; then
+                    ORACLE_OCI_LDFLAGS="$ORACLE_OCI_LDFLAGS -lnnz12"
+                    AC_MSG_RESULT([yes])
+                else
+                    AC_MSG_RESULT([no])
+                fi
             else
                 oracle_version_checked="no"
                 AC_MSG_RESULT([no])