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

2 files changed, 8 insertions, 123 deletions

diff --git a/minimal-examples/dbus-client/minimal-dbus-client/CMakeLists.txt b/minimal-examples/dbus-client/minimal-dbus-client/CMakeLists.txt
index 3e361b4e..ee42b478 100644
--- a/minimal-examples/dbus-client/minimal-dbus-client/CMakeLists.txt
+++ b/minimal-examples/dbus-client/minimal-dbus-client/CMakeLists.txt
@@ -1,75 +1,19 @@
 project(lws-minimal-dbus-client)
 cmake_minimum_required(VERSION 2.8)
+find_package(libwebsockets CONFIG REQUIRED)
+list(APPEND CMAKE_MODULE_PATH ${LWS_CMAKE_DIR})
 include(CheckCSourceCompiles)
 include(CheckLibraryExists)
+include(LwsCheckRequirements)
 
 set(SAMP lws-minimal-dbus-client)
 set(SRCS minimal-dbus-client.c)
 
-# If we are being built as part of lws, confirm current build config supports
-# reqconfig, else skip building ourselves.
-#
-# If we are being built externally, confirm installed lws was configured to
-# support reqconfig, else error out with a helpful message about the problem.
-#
-MACRO(require_lws_config reqconfig _val result)
-
-	if (DEFINED ${reqconfig})
-	if (${reqconfig})
-		set (rq 1)
-	else()
-		set (rq 0)
-	endif()
-	else()
-		set(rq 0)
-	endif()
-
-	if (${_val} EQUAL ${rq})
-		set(SAME 1)
-	else()
-		set(SAME 0)
-	endif()
-
-	if (LWS_WITH_MINIMAL_EXAMPLES AND NOT ${SAME})
-		if (${_val})
-			message("${SAMP}: skipping as lws being built without ${reqconfig}")
-		else()
-			message("${SAMP}: skipping as lws built with ${reqconfig}")
-		endif()
-		set(${result} 0)
-	else()
-		if (LWS_WITH_MINIMAL_EXAMPLES)
-			set(MET ${SAME})
-		else()
-			CHECK_C_SOURCE_COMPILES("#include <libwebsockets.h>\nint main(void) {\n#if defined(${reqconfig})\n return 0;\n#else\n fail;\n#endif\n return 0;\n}\n" HAS_${reqconfig})
-			if (NOT DEFINED HAS_${reqconfig} OR NOT HAS_${reqconfig})
-				set(HAS_${reqconfig} 0)
-			else()
-				set(HAS_${reqconfig} 1)
-			endif()
-			if ((HAS_${reqconfig} AND ${_val}) OR (NOT HAS_${reqconfig} AND NOT ${_val}))
-				set(MET 1)
-			else()
-				set(MET 0)
-			endif()
-		endif()
-		if (NOT MET)
-			if (${_val})
-				message(FATAL_ERROR "This project requires lws must have been configured with ${reqconfig}")
-			else()
-				message(FATAL_ERROR "Lws configuration of ${reqconfig} is incompatible with this project")
-			endif()
-		endif()
-
-	endif()
-ENDMACRO()
-
-
 set(requirements 1)
 require_lws_config(LWS_ROLE_DBUS 1 requirements)
 require_lws_config(LWS_WITH_CLIENT 1 requirements)
 
-if (requirements)
+if (NOT MSVC AND NOT WIN32 AND requirements)
 	add_executable(${SAMP} ${SRCS})
 
 	if (NOT LWS_PLAT_FREERTOS)
diff --git a/minimal-examples/dbus-client/minimal-dbus-ws-proxy-testclient/CMakeLists.txt b/minimal-examples/dbus-client/minimal-dbus-ws-proxy-testclient/CMakeLists.txt
index dbc8195f..c7443f5d 100644
--- a/minimal-examples/dbus-client/minimal-dbus-ws-proxy-testclient/CMakeLists.txt
+++ b/minimal-examples/dbus-client/minimal-dbus-ws-proxy-testclient/CMakeLists.txt
@@ -1,75 +1,16 @@
 project(lws-minimal-dbus-ws-proxy-testclient)
 cmake_minimum_required(VERSION 2.8)
+find_package(libwebsockets CONFIG REQUIRED)
+list(APPEND CMAKE_MODULE_PATH ${LWS_CMAKE_DIR})
 include(CheckCSourceCompiles)
 include(CheckLibraryExists)
-
-set(SAMP lws-minimal-dbus-ws-proxy-testclient)
-set(SRCS minimal-dbus-ws-proxy-testclient.c)
-
-# If we are being built as part of lws, confirm current build config supports
-# reqconfig, else skip building ourselves.
-#
-# If we are being built externally, confirm installed lws was configured to
-# support reqconfig, else error out with a helpful message about the problem.
-#
-MACRO(require_lws_config reqconfig _val result)
-
-	if (DEFINED ${reqconfig})
-	if (${reqconfig})
-		set (rq 1)
-	else()
-		set (rq 0)
-	endif()
-	else()
-		set(rq 0)
-	endif()
-
-	if (${_val} EQUAL ${rq})
-		set(SAME 1)
-	else()
-		set(SAME 0)
-	endif()
-
-	if (LWS_WITH_MINIMAL_EXAMPLES AND NOT ${SAME})
-		if (${_val})
-			message("${SAMP}: skipping as lws being built without ${reqconfig}")
-		else()
-			message("${SAMP}: skipping as lws built with ${reqconfig}")
-		endif()
-		set(${result} 0)
-	else()
-		if (LWS_WITH_MINIMAL_EXAMPLES)
-			set(MET ${SAME})
-		else()
-			CHECK_C_SOURCE_COMPILES("#include <libwebsockets.h>\nint main(void) {\n#if defined(${reqconfig})\n return 0;\n#else\n fail;\n#endif\n return 0;\n}\n" HAS_${reqconfig})
-			if (NOT DEFINED HAS_${reqconfig} OR NOT HAS_${reqconfig})
-				set(HAS_${reqconfig} 0)
-			else()
-				set(HAS_${reqconfig} 1)
-			endif()
-			if ((HAS_${reqconfig} AND ${_val}) OR (NOT HAS_${reqconfig} AND NOT ${_val}))
-				set(MET 1)
-			else()
-				set(MET 0)
-			endif()
-		endif()
-		if (NOT MET)
-			if (${_val})
-				message(FATAL_ERROR "This project requires lws must have been configured with ${reqconfig}")
-			else()
-				message(FATAL_ERROR "Lws configuration of ${reqconfig} is incompatible with this project")
-			endif()
-		endif()
-
-	endif()
-ENDMACRO()
-
+include(LwsCheckRequirements)
 
 set(requirements 1)
 require_lws_config(LWS_ROLE_DBUS 1 requirements)
 require_lws_config(LWS_WITH_CLIENT 1 requirements)
 
-if (requirements)
+if (NOT MSVC AND NOT WIN32 AND requirements)
 	add_executable(${SAMP} ${SRCS})
 
 	if (NOT LWS_PLAT_FREERTOS)