gnatmake -P/usr/gnat/share/examples/gnat/plugins/main.gpr demo -d -XExtension=so -XLinker_Option=None -XOS_Name=Unix 
gcc -c -g -gnat05 -I- -gnatA /usr/gnat/share/examples/gnat/plugins/demo.adb
gcc -c -g -gnat05 -I- -gnatA /usr/gnat/share/examples/gnat/plugins/extension_so.adb
gcc -c -g -gnat05 -I- -gnatA /usr/gnat/share/examples/gnat/plugins/hashed_strings.ads
gcc -c -g -gnat05 -I- -gnatA /usr/gnat/share/examples/gnat/plugins/plugins_unix.adb
gcc -c -g -gnat05 -I- -gnatA /usr/gnat/share/examples/gnat/plugins/h.adb
gnatbind -shared -I- -x /usr/gnat/share/examples/gnat/plugins/demo.ali
gnatlink /usr/gnat/share/examples/gnat/plugins/demo.ali -shared-libgcc -L/usr/gnat/share/examples/gnat/plugins/lbase -lbase -Wl,-rpath,/usr/gnat/share/examples/gnat/plugins/lbase:/usr/gnat/lib/gcc/i686-pc-linux-gnu/4.1.3/adalib/ -o /usr/gnat/share/examples/gnat/plugins/demo
/usr/gnat/share/examples/gnat/plugins/plugins_unix.o: In function `plugins__load':
/usr/gnat/share/examples/gnat/plugins/plugins_unix.adb:33: undefined reference to `dlopen'
/usr/gnat/share/examples/gnat/plugins/plugins_unix.adb:37: undefined reference to `dlerror'
/usr/gnat/share/examples/gnat/plugins/plugins_unix.o: In function `plugins__call__2':
/usr/gnat/share/examples/gnat/plugins/plugins_unix.adb:71: undefined reference to `dlsym'
/usr/gnat/share/examples/gnat/plugins/plugins_unix.adb:74: undefined reference to `dlerror'
/usr/gnat/share/examples/gnat/plugins/plugins_unix.o: In function `plugins__unload':
/usr/gnat/share/examples/gnat/plugins/plugins_unix.adb:92: undefined reference to `dlclose'
collect2: ld returned 1 exit status
gnatlink: error when calling /usr/gnat/bin/gcc
gnatmake: *** link failed.

process exited with status 4