Downgrade to mimalloc 2.1.9

I don't know the exact reason, but it looks like newer versions of mimalloc
has a problem with build reproducibility. Concretely, `dist.sh` produces
different binaries for my local builds and on GitHub Actions.

Author: rui314

third-party/mimalloc/.gitignore

@@ -1,4 +1,3 @@
-build
 ide/vs20??/*.db
 ide/vs20??/*.opendb
 ide/vs20??/*.user
@@ -9,5 +8,3 @@ docs/
 *.zip
 *.tar
 *.gz
-.vscode
-.DS_STore

third-party/mimalloc/CMakeLists.txt

@@ -241,6 +241,49 @@ jobs:
     workingDirectory: $(BuildType)
     displayName: CTest
 
+- job:
+  displayName: Ubuntu 20.04
+  pool:
+    vmImage:
+      ubuntu-20.04
+  strategy:
+    matrix:
+      Debug:
+        CC: gcc
+        CXX: g++
+        BuildType: debug
+        cmakeExtraArgs: -DCMAKE_BUILD_TYPE=Debug -DMI_DEBUG_FULL=ON
+      Debug++:
+        CC: gcc
+        CXX: g++
+        BuildType: debug-cxx
+        cmakeExtraArgs: -DCMAKE_BUILD_TYPE=Debug -DMI_DEBUG_FULL=ON -DMI_USE_CXX=ON
+      Debug Clang:
+        CC: clang
+        CXX: clang++
+        BuildType: debug-clang
+        cmakeExtraArgs: -DCMAKE_BUILD_TYPE=Debug -DMI_DEBUG_FULL=ON
+      Debug++ Clang:
+        CC: clang
+        CXX: clang++
+        BuildType: debug-clang-cxx
+        cmakeExtraArgs: -DCMAKE_BUILD_TYPE=Debug -DMI_DEBUG_FULL=ON -DMI_USE_CXX=ON
+      Release Clang:
+        CC: clang
+        CXX: clang++
+        BuildType: release-clang
+        cmakeExtraArgs: -DCMAKE_BUILD_TYPE=Release
+  steps:
+  - task: CMake@1
+    inputs:
+      workingDirectory: $(BuildType)
+      cmakeArgs: .. $(cmakeExtraArgs)
+  - script: make -j$(nproc) -C $(BuildType)
+    displayName: Make
+  - script: ctest --verbose --timeout 240
+    workingDirectory: $(BuildType)
+    displayName: CTest
+
 - job:
   displayName: macOS 15 (Sequoia)
   pool:

third-party/mimalloc/azure-pipelines.yml

@@ -1,14 +1,15 @@
 # Windows Override
 
-<span id="override_on_windows">We use a separate redirection DLL to override mimalloc on Windows</span> 
-such that we redirect all malloc/free calls that go through the (dynamic) C runtime allocator, 
-including those from other DLL's or libraries. As it intercepts all allocation calls on a low level, 
-it can be used on large programs that include other 3rd party components.
+<span id="override_on_windows">Dynamically overriding on mimalloc on Windows</span> 
+is robust and has the particular advantage to be able to redirect all malloc/free calls 
+that go through the (dynamic) C runtime allocator, including those from other DLL's or 
+libraries. As it intercepts all allocation calls on a low level, it can be used reliably 
+on large programs that include other 3rd party components.
 There are four requirements to make the overriding work well:
 
 1. Use the C-runtime library as a DLL (using the `/MD` or `/MDd` switch).
 
-2. Link your program explicitly with the `mimalloc.dll.lib` export library for
+2. Link your program explicitly with the `mimalloc.lib` export library for
    the `mimalloc.dll` -- which contains all mimalloc functionality.
    To ensure the `mimalloc.dll` is actually loaded at run-time it is easiest 
    to insert some call to the mimalloc API in the `main` function, like `mi_version()`
@@ -25,23 +26,6 @@ There are four requirements to make the overriding work well:
    list of the final executable (so it can intercept all potential allocations).
    You can use `minject -l <exe>` to check this if needed.
 
-```csharp
-┌──────────────┐                                                    
-│ Your Program │                                                    
-└────┬─────────┘                                                    
-     │                                                              
-     │ mi_version()  ┌───────────────┐     ┌───────────────────────┐
-     ├──────────────►│ mimalloc.dll  ├────►│ mimalloc-redirect.dll │
-     │               └──────┬────────┘     └───────────────────────┘
-     │                      ▼                                       
-     │ malloc() etc. ┌──────────────┐                               
-     ├──────────────►│ ucrtbase.dll │                               
-     │               └──────────────┘                               
-     │                                                              
-     │                                                              
-     └──────────────► ...                                           
-```
-
 For best performance on Windows with C++, it
 is also recommended to also override the `new`/`delete` operations (by including
 [`mimalloc-new-delete.h`](../include/mimalloc-new-delete.h) 

third-party/mimalloc/bin/mimalloc-redirect-arm64.dll

@@ -1,6 +1,6 @@
 set(mi_version_major 2)
-set(mi_version_minor 2)
-set(mi_version_patch 2)
+set(mi_version_minor 1)
+set(mi_version_patch 9)
 set(mi_version ${mi_version_major}.${mi_version_minor})
 
 set(PACKAGE_VERSION ${mi_version})