Add dyld_requires

Add an attribute to allow specifying requirements that are only needed
to satisfy the dynamic library loader (or the linker, when operating in
certain strict modes).

Because these are only needed by the build in limited cases (and
arguably are only "needed" to work around broken environments), this is
not being treated as a breaking schema change.

While this could conceivably have a `dyld_libraries` companion, that is
not being added at this time. (Anyway, `link_libraries` is discouraged,
and `dyld_libraries` would be as well.)

Fixes: #106

Author: mwoehlke

conf.py

@@ -13,7 +13,7 @@
 project = 'Common Package Specification'
 copyright = '2025, Matthew Woehlke'
 
-version_info = (0, 14, 0)
+version_info = (0, 14, 1)
 release = '.'.join(map(str, version_info))
 version = '.'.join(map(str, version_info[:2]))
 

schema.rst

@@ -307,6 +307,38 @@ Attribute names are case sensitive.
   the latter, when applicable to the source being compiled,
   shall have precedence.
 
+.. ----------------------------------------------------------------------------
+.. cps:attribute:: dyld_requires
+  :type: list(string)
+  :context: component configuration
+
+  Specifies additional components required by a component
+  which are needed only by the dynamic library loader.
+  Unlike `requires (component)`_ or `link_requires`_,
+  these are not used to resolve symbol references of the consumer,
+  but represent "private" implementation requirements
+  of the component on which this attribute appears.
+
+  Typically, such requirements represent a need
+  to ensure that the required component can be found at run time.
+  This is usually accomplished in one of three ways:
+
+  - Ensuring that the component resides
+    in a default / "system" search path.
+
+  - Encoding the component path in the binary
+    in a way that influences the dynamic library loader
+    (e.g. "RPATH").
+
+  - Providing the component path in an environment variable
+    which influences the dynamic library loader's search paths.
+
+  The last case requires external information to be provided;
+  this attribute facilitates tools generating that information.
+  In some instances, this external library search information
+  may also be required to successfully link components,
+  if the linker demands that all library references can be resolved.
+
 .. ----------------------------------------------------------------------------
 .. cps:attribute:: hints
   :type: list(string)