Fix build using MinGW.
Fix build using MinGW.

MinGW requires wincrypt.h.
GCC does not support #pragma comment, which trips Werror.

cubieb/json-c,colemancda/json-c,CyanogenMod/android_external_json-c,rgerhards/json-c,Nzbuu/json-c,colemancda/json-c,cubieb/json-c,PureSwift/json-c,rgerhards/json-c,Nzbuu/json-c,Amineahd/json-c,alagoutte/json-c,UAVmatrix/json-c,haoranzeus/json-c,Nzbuu/json-c,CyanogenMod/android_external_json-c,rgerhards/json-c,chenha0/json-c,Amineahd/json-c,UAVmatrix/json-c,colemancda/json-c,chenha0/json-c,UAVmatrix/json-c,alagoutte/json-c,PureSwift/json-c,CyanogenMod/android_external_json-c,cubieb/json-c,alagoutte/json-c,PureSwift/json-c,CyanogenMod/android_external_json-c,Nzbuu/json-c,Amineahd/json-c,chenha0/json-c,PureSwift/json-c,haoranzeus/json-c,haoranzeus/json-c,UAVmatrix/json-c