Add conditional define to allow users to compile against their own zlib's.

git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@784 67173fc5-114c-0410-ac8e-9d2fd5bffc1f

code/BlenderLoader.cpp

@@ -57,7 +57,11 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // zlib is needed for compressed blend files 
 #ifndef ASSIMP_BUILD_NO_COMPRESSED_BLEND
-#	include "../contrib/zlib/zlib.h"
+#	ifdef ASSIMP_BUILD_NO_OWN_ZLIB
+#		include <zlib.h>
+#	else
+#		include "../contrib/zlib/zlib.h"
+#	endif
 #endif
 
 using namespace Assimp;

code/Q3BSPFileImporter.cpp

@@ -45,7 +45,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "Q3BSPZipArchive.h"
 #include "Q3BSPFileParser.h"
 #include "Q3BSPFileData.h"
-#include "../contrib/zlib/zlib.h"
+
+#	ifdef ASSIMP_BUILD_NO_OWN_ZLIB
+#		include <zlib.h>
+#	else
+#		include "../contrib/zlib/zlib.h"
+#	endif
+
+
 #include "../include/aiTypes.h"
 #include "../include/aiMesh.h"
 #include <vector>

code/XFileParser.cpp

@@ -53,7 +53,11 @@ using namespace Assimp::XFile;
 
 #ifndef ASSIMP_BUILD_NO_COMPRESSED_X
 
-#include "../contrib/zlib/zlib.h"
+#	ifdef ASSIMP_BUILD_NO_OWN_ZLIB
+#		include <zlib.h>
+#	else
+#		include "../contrib/zlib/zlib.h"
+#	endif
 
 // Magic identifier for MSZIP compressed data
 #define MSZIP_MAGIC 0x4B43