Build wpa_supplicant 2.0 with libnl 3.2.21

Step 1: build libnl
1. untar libnl-3.2.21 to /usr/src
2. cd /usr/src/libnl-3.2.21
3. ./configure
    - Headers will be installed in ${prefix}/include/libnl3, therefore
      you will need to add "-I/usr/include/libnl3" to CFLAGS

    - The library basename was renamed to libnl-3, i.e. the SO names become
      libnl-3.so., libnl-route-3.so, etc.

    - libtool versioning was assumed, to ease detection of compatible library
      versions.
4. make
5. sudo make install

Step 2: build wpa_supplicant
1. cd to wpa_supplicant-2.0 folder
2. cd wpa_supplicant folder
3. Modify .config
CONFIG_LIBNL20=y
CONFIG_LIBNL32=y 
4. modify ../src/drivers/drivers.mak
ifdef CONFIG_LIBNL32
  DRV_LIBS += -lnl-3
  DRV_LIBS += -lnl-genl-3
  DRV_CFLAGS += -DCONFIG_LIBNL20 -I/usr/src/libnl-3.2.21/include
else

4. make
5. make install
6. cp /etc/local/lib/libnl* /etc/lib/.