diff --git a/cmake/macros/PackageConfig.cmake b/cmake/macros/PackageConfig.cmake
index 478cae0d61..8b14b86269 100644
--- a/cmake/macros/PackageConfig.cmake
+++ b/cmake/macros/PackageConfig.cmake
@@ -1,13 +1,14 @@
 # Filename: PackageConfig.cmake
 #
-# This modules defines functions which find and configures libraries
-# and packages for Panda3Ds configuration file headers (.h files).
+# This module defines functions which find and configure libraries
+# and packages for Panda3D.
 #
-# Assumes the file has already been found with find_package().
+# Assumes an attempt to find the package has already been made with
+# find_package(). (i.e. relies on packagename_FOUND variable)
 #
 # Function: package_option
 # Usage:
-#   package_option(package_name DOCSTRING
+#   package_option(package_name package_doc_string
 #                  [DEFAULT ON | OFF]
 #                  [LICENSE license])
 # Examples:
@@ -15,6 +16,24 @@
 #
 #       If no default is given, the default in normal
 #       builds is to enable all found third-party packages.
+#       In builds for redistribution, there is the additional requirement that
+#       the package be suitably-licensed.
+#
+#
+# Function: config_package
+# Usage:
+#   config_package(package_name "Package description" ["Config summary"])
+# Examples:
+#   config_package(OpenAL "OpenAL Audio Output")
+#   config_package(ROCKET "Rocket" "without Python bindings")
+#
+#
+# Function: show_packages
+# Usage:
+#   show_packages()
+#
+#   This prints the package usage report using the information provided in
+#   calls to config_package above.
 #
 #
 # Function: target_use_packages
@@ -24,10 +43,18 @@
 #   target_use_packages(mylib PYTHON PNG)
 #
 
-
 #
 # package_option
 #
+# In order to make sure no third-party licenses are inadvertently violated,
+# this imposes a few rules regarding license:
+# 1) If there is no license, no special restrictions.
+# 2) If there is a license, but the build is not flagged for redistribution,
+#    no special restrictions.
+# 3) If there is a license, and this is for redistribution, the package is
+#    forcibly defaulted off and must be explicitly enabled, unless the license
+#    matches a list of licenses suitable for redistribution.
+#
 function(package_option name)
   # Parse the arguments.
   set(command)
@@ -104,6 +131,8 @@ function(package_option name)
     set(PANDA_DID_SET_OPTION_${name} TRUE PARENT_SCOPE)
   endif()
 
+  set(PANDA_PACKAGE_DEFAULT_${name} "${default}")
+
   # Create the option.
   option("HAVE_${name}" "${cache_string}" "${default}")
   if(HAVE_${name})
@@ -115,6 +144,64 @@ function(package_option name)
   endif()
 endfunction()
 
+set(_ALL_CONFIG_PACKAGES CACHE INTERNAL "Internal variable")
+
+#
+# config_package
+#
+function(config_package name desc)
+  set(note "")
+  foreach(arg ${ARGN})
+    set(note "${arg}")
+  endforeach()
+
+  if(NOT PANDA_DID_SET_OPTION_${name})
+    message(SEND_ERROR "config_package(${name}) was called before package_option(${name}).
+                        This is a bug in the cmake build scripts.")
+  endif()
+
+  list(FIND _ALL_CONFIG_PACKAGES "${name}" called_twice)
+  if(called_twice GREATER -1)
+    message(SEND_ERROR "config_package(${name}) was called twice.
+                        This is a bug in the cmake build scripts.")
+  else()
+    list(APPEND _ALL_CONFIG_PACKAGES "${name}")
+    set(_ALL_CONFIG_PACKAGES "${_ALL_CONFIG_PACKAGES}" CACHE INTERNAL "Internal variable")
+  endif()
+
+  set(PANDA_PACKAGE_DESC_${name} "${desc}" PARENT_SCOPE)
+  set(PANDA_PACKAGE_NOTE_${name} "${note}" PARENT_SCOPE)
+endfunction()
+
+#
+# show_packages
+#
+function(show_packages)
+  message("")
+  message("Configuring support for the following optional third-party packages:")
+
+  foreach(package ${_ALL_CONFIG_PACKAGES})
+    set(desc "${PANDA_PACKAGE_DESC_${package}}")
+    set(note "${PANDA_PACKAGE_NOTE_${package}}")
+    if(HAVE_${package})
+      if(NOT note STREQUAL "")
+        message("+ ${desc} (${note})")
+      else()
+        message("+ ${desc}")
+      endif()
+    else()
+      if(NOT ${package}_FOUND)
+        set(reason "not found")
+      elseif(PANDA_PACKAGE_DEFAULT_${package})
+        set(reason "not requested")
+      else()
+        set(reason "disabled")
+      endif()
+      message("- ${desc} (${reason})")
+    endif()
+  endforeach()
+endfunction()
+
 #
 # target_use_packages
 #
diff --git a/dtool/Config.cmake b/dtool/Config.cmake
index 80548f5cad..af5ebf81e1 100644
--- a/dtool/Config.cmake
+++ b/dtool/Config.cmake
@@ -412,24 +412,6 @@ mark_as_advanced(ANDROID_NDK_HOME ANDROID_ABI ANDROID_STL
 # Now let's check for the presence of various thirdparty libraries.
 #
 
-# Is Eigen installed, and should Eigen replace internal linmath?
-find_package(Eigen3 QUIET)
-
-package_option(EIGEN
-  "Enables experimental support for the Eigen linear algebra library.
-If this is provided, Panda will use this library as the fundamental
-implementation of its own linmath library; otherwise, it will use
-its own internal implementation.  The primary advantage of using
-Eigen is SSE2 support, which is only activated if LINMATH_ALIGN
-is also enabled."
-  LICENSE "MPL-2")
-
-option(LINMATH_ALIGN
-  "This is required for activating SSE2 support using Eigen.
-Activating this does constrain most objects in Panda to 16-byte
-alignment, which could impact memory usage on very-low-memory
-platforms.  Currently experimental." ON)
-
 # Always include Eigen, because we include it pretty much everywhere.
 if(EIGEN3_FOUND)
   include_directories(${EIGEN3_INCLUDE_DIR})
diff --git a/dtool/LocalSetup.cmake b/dtool/LocalSetup.cmake
index fd8c2c1164..854de90914 100644
--- a/dtool/LocalSetup.cmake
+++ b/dtool/LocalSetup.cmake
@@ -188,18 +188,7 @@ else()
 endif()
 
 # Now go through all the packages and report whether we have them.
-message("")
-message("Configuring support for the following optional third-party packages:")
-if(HAVE_EIGEN)
-  message("+ Eigen linear algebra library")
-  if(LINMATH_ALIGN)
-    message("+   (vectorization enabled in build)")
-  else()
-    message("-   (vectorization NOT enabled in build)")
-  endif()
-else()
-  message("- Did not find Eigen linear algebra library")
-endif()
+show_packages()
 
 if(HAVE_OPENSSL)
   message("+ OpenSSL")
diff --git a/dtool/Package.cmake b/dtool/Package.cmake
index 35447f9dab..7ab874cf8a 100644
--- a/dtool/Package.cmake
+++ b/dtool/Package.cmake
@@ -1,3 +1,27 @@
+# Eigen
+find_package(Eigen3 QUIET)
+if(Eigen3_FOUND)
+  set(EIGEN_FOUND ON)
+endif()
+package_option(EIGEN
+  "Enables experimental support for the Eigen linear algebra library.
+If this is provided, Panda will use this library as the fundamental
+implementation of its own linmath library; otherwise, it will use
+its own internal implementation.  The primary advantage of using
+Eigen is SSE2 support, which is only activated if LINMATH_ALIGN
+is also enabled."
+  LICENSE "MPL-2")
+option(LINMATH_ALIGN
+  "This is required for activating SSE2 support using Eigen.
+Activating this does constrain most objects in Panda to 16-byte
+alignment, which could impact memory usage on very-low-memory
+platforms.  Currently experimental." ON)
+if(LINMATH_ALIGN)
+  config_package(EIGEN "Eigen linear algebra library" "vectorization enabled in build")
+else()
+  config_package(EIGEN "Eigen linear algebra library" "vectorization NOT enabled in build")
+endif()
+
 # Find and configure Miles Sound System
 find_package(Miles QUIET)
 #config_package(RAD_MSS "Miles Sound System")