The default config file for wpa_supplicant contains many examples but they all are uncommented. When trying to use wpa_supplicant without AUTOWPA set in a profile, it will not work until you manually comment/remove over twenty configuration examples. I think it would be better to comment out all examples except the last one which is:

# Wildcard match for SSID (plaintext APs only). This example select any
# open AP regardless of its SSID.
network={
key_mgmt=NONE
}

Actually it wouldn't hurt to have all those examples uncommented but wpa_supplicant seems to have been built incomplete, look at this:

# wpa_supplicant -d -w -i wlan0 -c /etc/wpa_supplicant.conf -Dwext
Initializing interface 'wlan0' conf '/etc/wpa_supplicant.conf' driver 'wext' ctrl_interface 'N/A' bridge 'N/A'
Configuration file '/etc/wpa_supplicant.conf' -> '/etc/wpa_supplicant.conf'
Reading configuration file '/etc/wpa_supplicant.conf'
ctrl_interface='/var/run/wpa_supplicant'
eapol_version=1
ap_scan=1
fast_reauth=1
Line 558: unknown EAP method 'SIM'
You may need to add support for this EAP method during wpa_supplicant
build time configuration.
See README for more information.
Line 558: failed to parse eap 'SIM'.
Line 561: failed to parse network block.
Line 568: unknown EAP method 'PSK'
You may need to add support for this EAP method during wpa_supplicant
build time configuration.
See README for more information.
Line 568: failed to parse eap 'PSK'.
Line 572: failed to parse network block.
Line 604: unknown EAP method 'FAST'
You may need to add support for this EAP method during wpa_supplicant
build time configuration.
See README for more information.
Line 604: failed to parse eap 'FAST'.
Line 610: failed to parse network block.
Line 615: unknown EAP method 'FAST'
You may need to add support for this EAP method during wpa_supplicant
build time configuration.
See README for more information.
Line 615: failed to parse eap 'FAST'.
Line 621: failed to parse network block.
Priority group 20
id=22 ssid='example'
Priority group 10
id=4 ssid='example'
Priority group 5
id=0 ssid='simple'
id=17 ssid='static-wep-test'
id=18 ssid='static-wep-test2'
Priority group 2
id=1 ssid='second ssid'
id=2 ssid='example'
id=5 ssid='example'
id=7 ssid='example'
Priority group 1
id=3 ssid='example'
Priority group 0
id=6 ssid='example'
id=8 ssid='example'
id=9 ssid=''
id=12 ssid='1x-test'
id=13 ssid='leap-example'
id=16 ssid='plaintext-test'
id=19 ssid='test adhoc'
id=20 ssid='example'
id=21 ssid='example'
id=23 ssid=''
Failed to read or parse configuration '/etc/wpa_supplicant.conf'.
Failed to add interface wlan0
Cancelling scan request
Cancelling authentication timeout