check expat part of config.log in om source

797 | #include <expat.h>
798 configure:19523: result: no
799 configure:19551: checking for expat.h
800 configure:19559: result: no
801 configure:19605: checking for X
802 configure:19840: result: libraries /usr/X11R6/lib, headers /usr/X11R6/include
803 configure:19868: checking for GDAL
804 configure:19877: result: yes
805 configure:19896: checking for OGR in GDAL
806 configure:19903: result: yes
807 configure:19946: looking for expat.h in /usr/local/include
808 configure:19950: checking for /usr/local/include/expat.h
809 configure:19971: c++ -c -O2 -fno-strict-aliasing -pipe -march=pentium-m  conftest.cpp >&5
810 In file included from /usr/include/sys/_types.h:33,
811                  from /usr/include/stdlib.h:42,
812                  from /usr/local/include/expat.h:17,
813                  from conftest.cpp:24:
814 /usr/include/machine/_types.h:51: error: expected unqualified-id before string constant
815 /usr/include/machine/_types.h:88: error: `__int8_t' does not name a type
816 configure:19977: $? = 1
817 configure: failed program was:
818 | /* confdefs.h.  */
819 | #define PACKAGE_NAME ""
820 | #define PACKAGE_TARNAME ""
821 | #define PACKAGE_VERSION ""
822 | #define PACKAGE_STRING ""
823 | #define PACKAGE_BUGREPORT ""
824 | #define PACKAGE "libopenmodeller"
825 | #define VERSION "0.4.1"
826 | #define STDC_HEADERS 1</expat.h>