By default, targets integrated as static libraries _will not_ get a module map, unless they opt-in by including `DEFINES_MODULE = YES` in their specification's `pod_target_xcconfig`

This allows us to avoid incomplete umbrella header warnings

While well-intentioned, they broke cross-project target dependency detection

xcodebuild fails if a framework target has PRODUCT_MODULE_NAME

Only for static libs at the moment, but this means the relative paths found in the module map will be importable

Because the aggregate target uses the same xcconfig as the user target, we have to disable embedding solely for the target, as it needs to be set to YES in the xcconfig

This ensures Xcode won’t try to automatically pull in modulemap files that it encounters, causing “duplicate definition of module” errors

Add support for modular header search paths, include "legacy" support

[SpecWithSource] Rename #spec_source for consistency with LazySpecification