CMake: Fix CMake bug which caused incorrect plugin manufacturer code to be generated

Please see the breaking changes doc for details.

BREAKING-CHANGES.txt

@@ -1,6 +1,37 @@
 JUCE breaking changes
 =====================
 
+Develop
+=======
+
+Change
+------
+A typo in the JUCEUtils CMake script that caused the wrong manufacturer code to
+be set in the compile definitions for a plugin was fixed.
+
+Possible Issues
+---------------
+The manufacturer code for plugins built under CMake with this version of JUCE
+will differ from the manufacturer code that was generated previously.
+
+Workaround
+----------
+If you have released plugins that used the old, incorrect manufacturer code and
+wish to continue using this code for backwards compatibility, add the following
+to your `juce_add_plugin` call:
+
+    USE_LEGACY_COMPATIBILITY_PLUGIN_CODE TRUE
+
+In most cases, this should not be necessary, and we recommend using the fixed
+behaviour.
+
+Rationale
+---------
+This change ensures that the manufacturer codes used by CMake projects match
+the codes that would be generated by the Projucer, improving compatibility
+when transitioning from the Projucer to CMake.
+
+
 Version 6.0.2
 =============
 

docs/CMake API.md

@@ -495,6 +495,13 @@ attributes directly to these creation functions, rather than adding them later.
     hosting plugins. Using this parameter should be preferred over using
     `target_compile_definitions` to manually set the `JUCE_PLUGINHOST_AU` preprocessor definition.
 
+- `USE_LEGACY_COMPATIBILITY_PLUGIN_CODE`
+  - May be either TRUE or FALSE (defaults to FALSE). If TRUE, will override the value of the
+    preprocessor definition "JucePlugin_ManufacturerCode" with the hex equivalent of "proj". This
+    option exists to maintain compatiblity with a previous, buggy version of JUCE's CMake support
+    which mishandled the manufacturer code property. Most projects should leave this option set to
+    its default value.
+
 - `COPY_PLUGIN_AFTER_BUILD`
   - Whether or not to install the plugin to the current system after building. False by default.
     If you want all of the plugins in a subdirectory to be installed automatically after building,

extras/Build/CMake/JUCEUtils.cmake

@@ -1527,9 +1527,15 @@ function(_juce_configure_plugin_targets target)
     get_target_property(project_version_string ${target} JUCE_VERSION)
     _juce_version_code(${project_version_string} project_version_hex)
 
-    get_target_property(project_manufacturer_code ${target} JUCE_PLUGIN_MANUFACTURERER_CODE)
+    get_target_property(project_manufacturer_code ${target} JUCE_PLUGIN_MANUFACTURER_CODE)
     get_target_property(project_plugin_code ${target} JUCE_PLUGIN_CODE)
 
+    get_target_property(use_legacy_compatibility_plugin_code ${target} JUCE_USE_LEGACY_COMPATIBILITY_PLUGIN_CODE)
+
+    if(use_legacy_compatibility_plugin_code)
+        set(project_manufacturer_code "project_manufacturer_code-NOTFOUND")
+    endif()
+
     _juce_to_char_literal(${project_manufacturer_code} project_manufacturer_code)
     _juce_to_char_literal(${project_plugin_code} project_plugin_code)
 
@@ -1897,6 +1903,7 @@ function(_juce_initialise_target target)
         AU_SANDBOX_SAFE
         AAX_CATEGORY
         PLUGINHOST_AU                   # Set this true if you want to host AU plugins
+        USE_LEGACY_COMPATIBILITY_PLUGIN_CODE
 
         VST_COPY_DIR
         VST3_COPY_DIR