Feat: allow for multiple find package overrides

As the title states. Before, it was only possible to override the find_package for a single package.

src/Index.cmake

@@ -30,9 +30,17 @@ macro (find_package)
 
 	if (AVAILABLE_SUB_PROJECTS)
 		string (TOLOWER "${ARGV0}" _pkg_low)
-		string (TOLOWER "${AVAILABLE_SUB_PROJECTS}" _sub_low)
+		set (_found_in_sub_projects OFF)
 
-		if (${_pkg_low} STREQUAL ${_sub_low})
+		foreach (_sub_project ${AVAILABLE_SUB_PROJECTS})
+			string (TOLOWER "${_sub_project}" _sub_low)
+			if (${_pkg_low} STREQUAL ${_sub_low})
+				set (_found_in_sub_projects ON)
+				break ()
+			endif ()
+		endforeach ()
+
+		if (_found_in_sub_projects)
 			message (WARNING "Package ${ARGV0} available as a sub project; skip find_package")
 		else ()
 			_find_package (${ARGV})