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."

CMakeModules/FindAndroidNDK.cmake

@@ -0,0 +1,45 @@
+# Locate AndroidNDK
+# This module defines
+# ANDROID_NDK
+# ANDROID_FOUND, if false, do not try to use AndroidNDK
+#
+
+FIND_PATH(ANDROID_NDK ndk-build
+    ${ANDROID_NDK}
+    NO_DEFAULT_PATH
+)
+
+IF(NOT ANDROID_NDK)
+    FIND_PATH(ANDROID_NDK ndk-build
+        $ENV{ANDROID_NDK}
+        $ENV{ANDROID_ROOT}
+        NO_DEFAULT_PATH
+    )
+ENDIF()
+
+IF(NOT ANDROID_NDK)
+    FIND_PATH(ANDROID_NDK ndk-build
+        # search for r5b
+        ~/android-ndk-r5b
+        ~/android_develop/android-ndk-r5b
+        ~/ndk-r5b
+        ~/android_develop/ndk-r5b
+        # search for r5
+        ~/android-ndk-r5
+        ~/android_develop/android-ndk-r5
+        ~/ndk-r5
+        ~/android_develop/ndk-r5
+        # search for r4-crystax
+        ~/android-ndk-r4-crystax
+        ~/android_develop/android-ndk-r4-crystax
+        ~/ndk-r4
+        ~/android_develop/ndk-r4
+    )
+ENDIF()
+ 
+SET(ANDROID_FOUND "NO")
+IF(ANDROID_NDK)
+  SET(ANDROID_FOUND "YES")
+  MESSAGE(STATUS "Android NDK found in: ${ANDROID_NDK}")
+ENDIF(ANDROID_NDK)
+