fix(build): resolve Windows MinGW memset_explicit linking error

libsodium-sys requires memset_explicit which is not available in older
MinGW toolchains. Added a C shim that provides a fallback implementation
using volatile pointers to prevent compiler optimization.

Changes:
- Added memset_s_shim.c with fallback memset_explicit implementation
- Updated build.rs to compile shim for Windows GNU targets
- Added cc crate as build dependency
- Set CFLAGS in CI to target Windows 8+ (_WIN32_WINNT=0x0602)
- Set SODIUM_STATIC=yes to force static libsodium build

Fixes linking error: undefined reference to memset_explicit

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitea/workflows/release-beta.yml

@@ -317,6 +317,10 @@ jobs:
           CARGO_TARGET_X86_64_PC_WINDOWS_GNU_LINKER: x86_64-w64-mingw32-gcc
           OPENSSL_NO_VENDOR: "0"
           OPENSSL_STATIC: "1"
+          # Fix memset_explicit missing symbol for libsodium on MinGW
+          CFLAGS_x86_64_pc_windows_gnu: "-D_WIN32_WINNT=0x0602"
+          SODIUM_LIB_DIR: ""
+          SODIUM_STATIC: "yes"
         run: |
           npm ci --legacy-peer-deps
           CI=true npx tauri build --target x86_64-pc-windows-gnu

src-tauri/.cargo/config.toml

@@ -9,3 +9,7 @@ rustflags = ["-C", "link-arg=-Wl,--exclude-all-symbols"]
 # Use system OpenSSL instead of vendoring from source (which requires Perl modules
 # unavailable on some environments and breaks clippy/check).
 OPENSSL_NO_VENDOR = "1"
+
+# Force libsodium to use minimal mode which avoids memset_explicit on Windows
+SODIUM_USE_PKG_CONFIG = "0"
+SODIUM_STATIC = "1"

src-tauri/Cargo.lock

@@ -6535,6 +6535,7 @@ dependencies = [
  "anyhow",
  "async-trait",
  "base64 0.22.1",
+ "cc",
  "chrono",
  "dirs 5.0.1",
  "docx-rs",

src-tauri/Cargo.toml

@@ -9,6 +9,7 @@ crate-type = ["staticlib", "cdylib", "rlib"]
 
 [build-dependencies]
 tauri-build = { version = "2.6", features = [] }
+cc = "1.0"
 
 [dependencies]
 tauri = { version = "2", features = [] }

src-tauri/build.rs

@@ -5,6 +5,16 @@ fn main() {
     println!("cargo:rerun-if-changed=.git/refs/heads/master");
     println!("cargo:rerun-if-changed=.git/refs/tags");
 
+    // Compile memset_explicit shim for Windows MinGW
+    if std::env::var("CARGO_CFG_TARGET_OS").unwrap_or_default() == "windows"
+        && std::env::var("CARGO_CFG_TARGET_ENV").unwrap_or_default() == "gnu"
+    {
+        cc::Build::new()
+            .file("memset_s_shim.c")
+            .compile("memset_shim");
+        println!("cargo:rerun-if-changed=memset_s_shim.c");
+    }
+
     tauri_build::build()
 }
 

src-tauri/memset_s_shim.c

@@ -0,0 +1,28 @@
+// Shim for memset_explicit on MinGW which doesn't provide it
+// This is needed for libsodium's secure memory clearing
+
+#if defined(_WIN32) && defined(__MINGW32__)
+
+#include <string.h>
+
+// memset_explicit is available in Windows 8+ but MinGW headers don't always declare it
+// Provide a fallback implementation using SecureZeroMemory if available,
+// or a volatile memset to prevent compiler optimization
+void *memset_explicit(void *s, int c, size_t n) {
+    // Try to use Windows API if available
+    #ifdef _WIN32_WINNT
+        #if _WIN32_WINNT >= 0x0602  // Windows 8+
+            extern void *memset_s(void *, size_t, int, size_t);
+            return memset_s(s, n, c, n);
+        #endif
+    #endif
+
+    // Fallback: use volatile to prevent optimization
+    volatile unsigned char *p = (volatile unsigned char *)s;
+    while (n--) {
+        *p++ = (unsigned char)c;
+    }
+    return s;
+}
+
+#endif