cmake: Use cmake's built-in TestForSSTREAM when testing for sstream.

The original test for SSTREAM actually tested for STRSTREAM.  Instead
of fixing the logic to test for SSTREAM, it seemed easier just to use
cmake's built-in macro to perform the test.

Author: snrkiwi

Configure.cmake

@@ -2,16 +2,9 @@
 # LOG4CPP_HAVE_SSTREAM
 ###########################################################
 
-FILE(WRITE "${CMAKE_CURRENT_BINARY_DIR}/configure-tryouts/strstream.cpp.in"
-"#include <strstream>\n"
-"int main()\n"
-"{\n"
-"	std::ostrstream	os;\n"
-"	os.str();\n"
-"	return 0;\n"
-"}")
-CONFIGURE_FILE(${CMAKE_CURRENT_BINARY_DIR}/configure-tryouts/strstream.cpp.in ${CMAKE_CURRENT_BINARY_DIR}/configure-tryouts/strstream.cpp)
-TRY_COMPILE(LOG4CPP_HAVE_SSTREAM ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_BINARY_DIR}/configure-tryouts/strstream.cpp OUTPUT_VARIABLE OUTPUT)
+INCLUDE(TestForSSTREAM)
+
+SET (LOG4CPP_HAVE_SSTREAM NOT ${CMAKE_NO_ANSI_STRING_HEADERS})
 
 ###########################################################
 # LOG4CPP_HAVE_GETTIMEOFDAY