*/Toolchain.cmake: Set CMAKE_FIND_ROOT_PATH_LIBRARY/INCLUDE to ONLY

For some reason, the default setting in all Toolchain.cmake
is:
```
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY BOTH)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE BOTH)
```

For cross-compilation, CMAKE_FIND_ROOT_PATH_MODE_PROGRAM=NEVER
makes sense (we only want to find executables in host system root),
but CMAKE_FIND_ROOT_PATH_MODE_LIBRARY/INCLUDE should be set
to ONLY, otherwise cmake may find libraries in host system root,
and try to link with incompatible libraries (instead of
cross-compilation sysroot).

Fixes #431.

android-arm/Toolchain.cmake

@@ -17,8 +17,8 @@ set(CMAKE_SHARED_LINKER_FLAGS "-llog")
 
 set(CMAKE_FIND_ROOT_PATH $ENV{CROSS_ROOT})
 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
-set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY BOTH)
-set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE BOTH)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
 set(CMAKE_SYSROOT $ENV{CROSS_ROOT}/sysroot)
 
 set(CMAKE_CROSSCOMPILING_EMULATOR /usr/bin/qemu-arm)