Add custom allocator feature (#175)

Author: AlixANNERAUD

lvgl/Cargo.toml

@@ -73,6 +73,9 @@ nightly = []
 # function before constructing or using anything LVGL-related.
 unsafe_no_autoinit = []
 
+# This feature is required to use the custom allocator in lvgl (`LV_MEM_CUSTOM=1` in `lv_conf.h`).
+custom_allocator = []
+
 [build-dependencies]
 quote = "1.0.23"
 proc-macro2 = "1.0.51"

lvgl/src/lib.rs

@@ -97,6 +97,7 @@ pub fn init() {
 ///
 /// After calling, ensure existing LVGL-related values are not accessed even if
 /// LVGL is reinitialized.
+#[cfg(not(feature = "custom_allocator"))]
 pub unsafe fn deinit() {
     unsafe {
         if IS_INIT {