From Rafa Gaitan and Jorge Izquierdo, build support for Android NDK.

"- In order to build against GLES1 we execute:
$ mkdir build_android_gles1
$ cd build_android_gles1
$ cmake .. -DOSG_BUILD_PLATFORM_ANDROID=ON -DDYNAMIC_OPENTHREADS=OFF
-DDYNAMIC_OPENSCENEGRAPH=OFF -DANDROID_NDK=<path_to_android_ndk>/
-DOSG_GLES1_AVAILABLE=ON -DOSG_GL1_AVAILABLE=OFF
-DOSG_GL2_AVAILABLE=OFF -DOSG_GL_DISPLAYLISTS_AVAILABLE=OFF -DJ=2
-DOSG_CPP_EXCEPTIONS_AVAILABLE=OFF
$ make
 If all is correct you will have and static OSG inside:
build_android_gles1/bin/ndk/local/armeabi.

- GLES2 is not tested/proved, but I think it could be possible build
it with the correct cmake flags.
- The flag -DJ=2 is used to pass to the ndk-build the number of
processors to speed up the building.
- make install is not yet supported."

src/osgPlugins/bsp/BITSET.cpp

@@ -9,6 +9,7 @@
 #include "memory.h"
 #include "BITSET.h"
 
+#include <cstring>
 
 bool BITSET::Init(int numberOfBits)
 {