Link against Mac OSX 10.5 SDK if building on 10.6.
Link against Mac OSX 10.5 SDK if building on 10.6.

So that tools built on Snow Leopard (10.6) can be used on Leopard (10.5).

Change-Id: I99745ecbe2ad11feaae31d5be31c34c2e0ad7cc5

knone1/platform_manifest,Hybrid-Power/startsync,hagar006/platform_manifest,see4ri/lolili,xorware/android_build,pranav01/platform_manifest,xorware/android_build,xorware/android_build,RR-msm7x30/platform_manifest,ND-3500/platform_manifest,xorware/android_build,fallouttester/platform_manifest,xorware/android_build