cmakelist: Augean Stables refactor

Establish a new distributed CMake architecture with CMake code related to
a source directory moving to be in the subdir in its own CMakeLists.txt.
In particular, there's now one in ./lib which calls through to ones
further down the directory tree like ./lib/plat/xxx, ./lib/roles/xxx etc.

This cuts the main CMakelists.txt from 98KB -> 33KB, about a 66% reduction,
and it's much easier to maintain sub-CMakeLists.txt that are in the same
directory as the sources they manage, and conceal all the details that that
level.

Child CMakelists.txt become responsible for:

 - include_directories() definition (this is not supported by CMake
   directly, it passes it back up via PARENT_SCOPE vars in helper
   macros)

 - Addition child CMakeLists.txt inclusion, for example toplevel ->
   role -> role subdir

 - Source file addition to the build

 - Dependent library path resolution... this is now a private thing
   in the child CMakeLists.txt, it just passes back any adaptations
   to include_directories() and the LIB_LIST without filling the
   parent namespace with the details

1 files changed, 57 insertions, 0 deletions

diff --git a/lib/abstract/CMakeLists.txt b/lib/abstract/CMakeLists.txt
new file mode 100644
index 00000000..3496c6ee
--- /dev/null
+++ b/lib/abstract/CMakeLists.txt
@@ -0,0 +1,57 @@
+#
+# libwebsockets - small server side websockets and web server implementation
+#
+# Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to
+# deal in the Software without restriction, including without limitation the
+# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+# sell copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
+#
+# The strategy is to only export to PARENT_SCOPE
+#
+#  - changes to LIB_LIST
+#  - changes to SOURCES
+#  - includes via include_directories
+#
+# and keep everything else private
+
+include_directories(.)
+
+list(APPEND SOURCES
+	abstract/abstract.c
+)
+if (LWS_WITH_SEQUENCER)
+	list(APPEND SOURCES
+		abstract/test-sequencer.c)
+endif()
+
+list(APPEND SOURCES
+	abstract/transports/unit-test.c)
+	
+#if (LWS_WITH_SMTP)
+#	list(APPEND SOURCES
+#		abstract/protocols/smtp/smtp.c
+#		abstract/protocols/smtp/smtp-sequencer.c
+#		)
+#endif()
+
+#
+# Keep explicit parent scope exports at end
+#
+
+exports_to_parent_scope()
+