Fixed Linking error for libglut.

[mark-bchoi]

Hi,

I try to build libfreenect-0.5.2 and found link error.

Affer some googling, this error is caused by find_package(GLUT) which would be applicable for Apple. linux would have used freeglut.

| /home/bchoi/nvidia-yocto-bsp/bchoi-build/tmp/work/armv8a-oe4t-linux/libfreenect/0.5.2/recipe-sysroot-native/usr/bin/aarch64-oe4t-linux/../../libexec/aarch64-oe4t-linux/gcc/aarch64-oe4t-linux/13.3.0/ld: examples/CMakeFiles/freenect-regview.dir/regview.c.o: in function `DrawGLScene':
| /usr/src/debug/libfreenect/0.5.2/examples/regview.c:134:(.text+0x20c): undefined reference to `glutSwapBuffers'
| /home/bchoi/nvidia-yocto-bsp/bchoi-build/tmp/work/armv8a-oe4t-linux/libfreenect/0.5.2/recipe-sysroot-native/usr/bin/aarch64-oe4t-linux/../../libexec/aarch64-oe4t-linux/gcc/aarch64-oe4t-linux/13.3.0/ld: /usr/src/debug/libfreenect/0.5.2/examples/regview.c:138:(.text+0x254): undefined reference to `glutGet'
| /home/bchoi/nvidia-yocto-bsp/bchoi-build/tmp/work/armv8a-oe4t-linux/libfreenect/0.5.2/recipe-sysroot-native/usr/bin/aarch64-oe4t-linux/../../libexec/aarch64-oe4t-linux/gcc/aarch64-oe4t-linux/13.3.0/ld: examples/CMakeFiles/freenect-regview.dir/regview.c.o: in function `idle':
| /usr/src/debug/libfreenect/0.5.2/examples/regview.c:91:(.text+0x6e8): undefined reference to `glutPostRedisplay'
| /home/bchoi/nvidia-yocto-bsp/bchoi-build/tmp/work/armv8a-oe4t-linux/libfreenect/0.5.2/recipe-sysroot-native/usr/bin/aarch64-oe4t-linux/../../libexec/aarch64-oe4t-linux/gcc/aarch64-oe4t-linux/13.3.0/ld: examples/CMakeFiles/freenect-regview.dir/regview.c.o: in function `keyPressed':
| /usr/src/debug/libfreenect/0.5.2/examples/regview.c:150:(.text+0x740): undefined reference to `glutDestroyWindow'
| /home/bchoi/nvidia-yocto-bsp/bchoi-build/tmp/work/armv8a-oe4t-linux/libfreenect/0.5.2/recipe-sysroot-native/usr/bin/aarch64-oe4t-linux/../../libexec/aarch64-oe4t-linux/gcc/aarch64-oe4t-linux/13.3.0/ld: examples/CMakeFiles/freenect-regview.dir/regview.c.o: in function `gl_threadfunc':
| /usr/src/debug/libfreenect/0.5.2/examples/regview.c:200:(.text+0x950): undefined reference to `glutInit'

I fixed this error with following patch.

diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index c37b61a..1336d78 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -14,7 +14,12 @@ install(TARGETS freenect-camtest freenect-wavrecord
 set(THREADS_USE_PTHREADS_WIN32 true)
 find_package(Threads)
 find_package(OpenGL)
-find_package(GLUT)
+if(APPLE)
+  find_package(GLUT)
+else ()
+  set(GLUT_FOUND true)
+  find_library(GLUT_LIBRARY NAMES glut glut32 freeglut)
+endif ()

 if (Threads_FOUND AND OPENGL_FOUND AND GLUT_FOUND)
   include_directories(${THREADS_PTHREADS_INCLUDE_DIR} ${OPENGL_INCLUDE_DIR} ${GLUT_INCLUDE_DIR})

BR,
Mark