Add -dead_strip_dylibs linker option
Fixed potential crash.

Committed with minor changes.

Patch-from: Ant <ant@dervishsoftware.com>
Added more flexible search for command-line tools.

Committed with numerous changes from original patch.

Original-patch-from: Ant <ant@dervishsoftware.com>
DropBox.m: eliminate compiler warning

NSBorderType is of type NSUInteger which is either 32
or 64 bits in size.  Replace the '%d' formatter with
'%u' and cast to unsigned to avoid the warning.
Fix pointer-as-int use to avoid warnings

The dyld_stub_binding_helper value is actually same size as a
void *.  When building LP64, it does not fit in a uint32_t and
cannot be swapped by OSSwapInt32.

Change the variable it's stored in to uintptr_t and then use the
new OSSwapIntPtr macro to swap it properly for both 32 and 64 bits.