Compiling as Objective-C, although I tried pure c++ earlier and got the same errors in 64bit.
mongoose.c:488:66: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'socklen_t' (aka 'unsigned int')
mongoose.c:543:20: Implicit conversion loses integer precision: 'unsigned long' to 'int'
mongoose.c:543:49: Implicit conversion loses integer precision: 'unsigned long' to 'int'
mongoose.c:705:40: Implicit conversion loses integer precision: 'long' to 'int'
mongoose.c:707:54: Implicit conversion loses integer precision: 'long' to 'int'
mongoose.c:859:19: Implicit conversion loses integer precision: 'long' to 'int'
mongoose.c:904:32: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:904:54: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:2053:31: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:2522:35: Implicit conversion loses integer precision: 'unsigned long' to 'int'
mongoose.c:2523:45: Implicit conversion loses integer precision: 'unsigned long' to 'int'
mongoose.c:2704:13: Implicit conversion loses integer precision: 'long' to 'int'
mongoose.c:2862:13: Implicit conversion loses integer precision: 'ssize_t' (aka 'long') to 'int'
mongoose.c:2884:13: Implicit conversion loses integer precision: 'ssize_t' (aka 'long') to 'int'
mongoose.c:2890:13: Implicit conversion loses integer precision: 'ssize_t' (aka 'long') to 'int'
mongoose.c:3003:21: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:3008:44: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:3371:36: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:3434:18: Implicit conversion loses integer precision: 'unsigned long' to 'int'
mongoose.c:4048:44: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:4080:24: Implicit conversion loses integer precision: 'unsigned long' to 'int'
mongoose.c:4375:22: Implicit conversion loses integer precision: 'unsigned long' to 'int'
mongoose.c:4419:36: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:4444:29: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:4451:29: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:4459:25: Implicit conversion loses integer precision: 'size_t' (aka 'unsigned long') to 'int'
mongoose.c:4626:27: Implicit conversion loses integer precision: 'unsigned long' to 'int'
mongoose.c:4638:27: Implicit conversion loses integer precision: 'unsigned long' to 'int'