Add cmake_build.txt and fix a small CMake issue

The cmake_build.txt is for Mac only right now, so we'll probably
want to try and figure out how to make it generic enough for all
platforms.

CMakeLists.txt

@@ -347,14 +347,15 @@ find_package( OpenGL QUIET )
 #     .../bin/Debug//
 # or:
 #     .../bin//Debug
-set( _DEST "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${CMAKE_CFG_INTDIR}/${CMAKE_BUILD_TYPE}" )
+set( _DESTDIR "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${CMAKE_CFG_INTDIR}/${CMAKE_BUILD_TYPE}" )
+set( _DEST "${_DESTDIR}" )
 set( _EXEDIR "${_DEST}" )
 string( REGEX REPLACE "/+$" "" _EXEDIR "${_EXEDIR}" )
 
 # Adjust them for the Mac
 if( CMAKE_SYSTEM_NAME MATCHES "Darwin" )
    set( _DEST "${_DEST}/Audacity.app/Contents" )
-   set( _EXEDIR "${_DEST}/Macos" )
+   set( _EXEDIR "${_DEST}/MacOS" )
 endif()
 
 set( _PREFIX "${CMAKE_INSTALL_PREFIX}" )

mac/cmake_build.txt

@@ -0,0 +1,141 @@
+Instructions for building on macOS using CMake.
+
+Building on macOS has been made much simpler with the Audacity 2.4.0
+release. Still, read this document throughly before starting.
+
+1) Get and install the latest Xcode version available your macOS version:
+
+      MacOS                   Xcode Version (as of Mar 2020)
+      Catalina - 10.15        11.3
+      Mojave - 10.14          10.3
+      High Sierra - 10.13     9.4.1
+      Sierra - 10.12          9.2
+      El Capitan - 10.11      8.2.1
+      Yosemite - 10.10        7.2.1
+
+2) Clone the Audacity repository:
+
+      git clone https://github.com/audacity/audacity
+
+3) Clone wxWidgets 3.1.1:
+
+      git clone --recurse-submodules https://github.com/audacity/wxWidgets.git
+
+   Ensure that you clone with the "--recurse-submodules" option, and do not
+   just download the Zip package, otherwise there will be required components
+   missing.
+
+   Don't be tempted to use wxWidgets already installed by a package manager
+   such as Homebrew because this will cause problems.
+
+   We have applied some Audacity specific patches to wxWidgets to better 
+   support VoiceOver, so please use the audacity-fixes-3.1.1 branch. It's
+   the default branch on our GitHub copy:
+
+      https://github.com/audacity/wxWidgets/tree/audacity-fixes-3.1.1
+
+   You can be certain the correct branch is active with:
+
+      git checkout audacity-fixes-3.1.1
+
+4) Change directory to the folder where wxWidgets was cloned and build it using:
+
+      sudo <path to Audacity source>/mac/scripts/build_wxwidgets
+
+5) The config command should return "3.1.1" if the install was successful:
+
+      /usr/local/x86_64/bin/wx-config --version
+
+6) Now that you have wxWidgets installed, edit your .bash_profile and add:
+
+      export WX_CONFIG=/usr/local/x86_64/bin/wx-config
+
+7) Download the CMake 3.16.4 DMG from:
+
+      https://cmake.org/download
+
+8) Double click the DMG, follow the prompts and drag the CMake app to the
+   Applications folder.
+
+   If you will be building from the command line, open the CMake application
+   and click the "Tools -> How to Install For Command Line Use" menu. It will
+   give you additional instructions on making CMake available to the command
+   line.
+
+   You are now ready to start building Audacity.
+
+BUILDING USING THE CMAKE GUI
+
+   NOTE: Building with the GUI interface will result in the downloading of
+         another copy of wxWidgets from Audacity.
+
+1) Open the app.
+
+2) Click the "Browse Source..." button and locate the top of your Audacity
+   source tree, then click the "Open" button.
+
+3) Click the "Browse Build..." button and find the location where you want to
+   put the build (use the "New Folder" button at the bottom left to create a
+   new folder).
+
+   This folder does not have to be in or even near the source tree, but it
+   must not be the same as the source tree. However, it is common to make it
+   a subdirectory of the Audacity source tree.
+
+4) Click the "Configure" button and when the dialog pops up, select "Xcode" for
+   the generator, then click the "Done" button.
+
+5) Click the "Generate" button to create the Xcode project.
+
+6) Now you can either click the "Open Project" button or go to your "Build" folder in
+   Finder and open the Xcode project as normal.
+
+BUILDING FROM THE COMMAND LINE
+
+1) Change directory to your Audacity source tree.
+
+      cd audacity
+
+2) Create the "build" folder (name it anything you like):
+
+      mkdir bld
+
+3) Change to the "build" folder:
+
+      cd bld
+
+4) Configure and generate the Xcode project:
+
+      cmake -G Xcode ..
+
+5) Build Audacity using the CMake command or xcodebuild:
+
+      cmake --build . --config Release
+
+      xcodebuild --configuration Release
+
+   The "Audacity.app" bundle will be in the "bin/Release" subdirectory of your
+   "build" folder, so you can start it via Finder or:
+
+      open bin/Release/Audacity.app
+
+Notes:
+
+   - If you'd like to get a completely clean build, just delete "build" folder
+     and return to step 2 above.
+
+   - Once the Xcode project is generated, you shouldn't have to "configure" or
+     "generate" again as it will be done for you automatically after pulling
+     updates and building.
+
+     For example:
+
+        cd <audacity> directory
+        git pull
+        cd bld
+        cmake --build . --config Release
+
+   - Instructions on optional signing of DMGs, showing languages other than English,
+     and other useful information can be found on our wiki at: 
+     http://wiki.audacityteam.org/wiki/Building_On_Mac
+

src/CMakeLists.txt

@@ -1198,6 +1198,7 @@ elseif( CMAKE_SYSTEM_NAME MATCHES "Darwin" )
          # Add the resources
          RESOURCE "${MAC_RESOURCES};${RESOURCES}"
    )
+   set_target_property_all( ${TARGET} RUNTIME_OUTPUT_DIRECTORY "${_DESTDIR}" )
 
    # These sources must be compiled as Objective C++
    set_source_files_properties(
@@ -1235,7 +1236,7 @@ elseif( CMAKE_SYSTEM_NAME MATCHES "Darwin" )
          TARGET
             ${TARGET}
          COMMAND
-            sh -c "TARGET_BUILD_DIR=${_DEST} EXECUTABLE_PATH=Macos/${_EXE} FRAMEWORKS_FOLDER_PATH=Frameworks ${topdir}/mac/scripts/install_wxlibs.sh"
+            sh -c "TARGET_BUILD_DIR=${_DEST} EXECUTABLE_PATH=MacOS/${_EXE} FRAMEWORKS_FOLDER_PATH=Frameworks ${topdir}/mac/scripts/install_wxlibs.sh"
          POST_BUILD
       )
    endif()