Updates the cmake build system

It's still has some work, but it successfully builds on
all 3 main platforms.  Some of the outstanding items
include:

   Install target testing (mostly important for Linux)
   CMakeList clean up and comments
   Debug and Release build verification
   Audit of compile/link options
   Need a Mac signed and notarized build
   (and probably more)

cmake-proxies/portmidi/CMakeLists.txt

@@ -1,10 +1,53 @@
-cmake_minimum_required(VERSION 2.8.11)
 
-set(TARGET portmidi)
-set(TARGET_SOURCE ${LIB_SRC_DIRECTORY}${TARGET})
+add_library( ${TARGET} STATIC )
+
+list( APPEND SOURCES
+   PRIVATE
+      ${TARGET_ROOT}/pm_common/portmidi.c
+      ${TARGET_ROOT}/pm_common/pmutil.c
+      ${TARGET_ROOT}/porttime/porttime.c
+      $<$<PLATFORM_ID:Windows>:${TARGET_ROOT}/pm_win/pmwin.c>
+      $<$<PLATFORM_ID:Windows>:${TARGET_ROOT}/pm_win/pmwinmm.c>
+      $<$<PLATFORM_ID:Windows>:${TARGET_ROOT}/porttime/ptwinmm.c>
+      $<$<PLATFORM_ID:Darwin>:${TARGET_ROOT}/pm_mac/finddefault.c>
+      $<$<PLATFORM_ID:Darwin>:${TARGET_ROOT}/pm_mac/pmmac.c>
+      $<$<PLATFORM_ID:Darwin>:${TARGET_ROOT}/pm_mac/pmmacosxcm.c>
+      $<$<PLATFORM_ID:Darwin>:${TARGET_ROOT}/pm_mac/readbinaryplist.c>
+      $<$<PLATFORM_ID:Darwin>:${TARGET_ROOT}/porttime/ptmacosx_mach.c>
+      $<$<PLATFORM_ID:Linux>:${TARGET_ROOT}/pm_linux/finddefault.c>
+      $<$<PLATFORM_ID:Linux>:${TARGET_ROOT}/pm_linux/pmlinux.c>
+      $<$<PLATFORM_ID:Linux>:${TARGET_ROOT}/pm_linux/pmlinuxalsa.c>
+      $<$<PLATFORM_ID:Linux>:${TARGET_ROOT}/porttime/ptlinux.c>
+)
+
+list( APPEND INCLUDES
+   PRIVATE
+      ${TARGET_ROOT}/pm_common
+      ${TARGET_ROOT}/porttime
+      $<$<PLATFORM_ID:Windows>:${TARGET_ROOT}/pm_win>
+      $<$<PLATFORM_ID:Linux>:${TARGET_ROOT}/pm_linux>
+      $<$<PLATFORM_ID:Darwin>:${TARGET_ROOT}/pm_win>
+)
+
+list( APPEND DEFINES
+   PRIVATE
+      $<$<PLATFORM_ID:Linux>:PMALSA=1>
+)
+
+list( APPEND OPTIONS
+   PRIVATE
+      $<$<PLATFORM_ID:Linux>:
+         -Wno-pointer-to-int-cast
+         -Wno-int-to-pointer-cast
+         -Wno-implicit-function-declaration
+      >
+)
+
+organize_source( "${TARGET_ROOT}" "" "${SOURCES}" )
+target_sources( ${TARGET} PRIVATE ${SOURCES} )
+target_compile_definitions( ${TARGET} PRIVATE ${DEFINES} )
+target_compile_features( ${TARGET} PRIVATE ${FEATURES} )
+target_compile_options( ${TARGET} PRIVATE ${OPTIONS} )
+target_include_directories( ${TARGET} PRIVATE ${INCLUDES} )
+target_link_libraries( ${TARGET} PRIVATE ${LIBRARIES} )
 
-set(CMAKE_CACHEFILE_DIR ${CMAKE_BINARY_DIR})
-add_subdirectory( "${TARGET_SOURCE}" "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}" EXCLUDE_FROM_ALL )
-set_target_properties(portmidi-static PROPERTIES
-    OSX_ARCHITECTURES ""
-    OUTPUT_NAME ${TARGET})