Add dgeev implementation for WASM

Package.swift

@@ -18,12 +18,19 @@ let package = Package(
         .target(
             name: "pocketFFT"
             ),
+        .target(
+            name: "CLAPACKHelper",
+            dependencies: [
+                .product(name: "CLAPACK", package: "CLAPACK"),
+            ],
+            publicHeadersPath: "include"
+            ),
         .target(
             name: "Matft",
             dependencies: [
                 .product(name: "Collections", package: "swift-collections"),
                 "pocketFFT",
-                .product(name: "CLAPACK", package: "CLAPACK", condition: .when(platforms: [.wasi])),
+                .target(name: "CLAPACKHelper", condition: .when(platforms: [.wasi])),
             ]),
         .testTarget(
             name: "MatftTests",

Sources/CLAPACKHelper/clapack_helper.c

@@ -0,0 +1,48 @@
+// clapack_helper.c
+// Wrapper implementations that call CLAPACK functions with correct void signatures.
+
+#include "include/clapack_helper.h"
+
+// Declare the actual CLAPACK functions with correct void return type
+// These are the real signatures from the f2c-generated code
+extern void dgetrf_(
+    clapack_int *m,
+    clapack_int *n,
+    double *a,
+    clapack_int *lda,
+    clapack_int *ipiv,
+    clapack_int *info
+);
+
+extern void dgetri_(
+    clapack_int *n,
+    double *a,
+    clapack_int *lda,
+    clapack_int *ipiv,
+    double *work,
+    clapack_int *lwork,
+    clapack_int *info
+);
+
+void clapack_dgetrf_wrapper(
+    clapack_int *m,
+    clapack_int *n,
+    double *a,
+    clapack_int *lda,
+    clapack_int *ipiv,
+    clapack_int *info
+) {
+    dgetrf_(m, n, a, lda, ipiv, info);
+}
+
+void clapack_dgetri_wrapper(
+    clapack_int *n,
+    double *a,
+    clapack_int *lda,
+    clapack_int *ipiv,
+    double *work,
+    clapack_int *lwork,
+    clapack_int *info
+) {
+    dgetri_(n, a, lda, ipiv, work, lwork, info);
+}

Sources/CLAPACKHelper/include/clapack_helper.h

@@ -0,0 +1,32 @@
+// clapack_helper.h
+// This header provides correct function signatures for CLAPACK functions.
+// The CLAPACK header incorrectly declares these as returning int,
+// but the actual f2c-generated implementation returns void.
+
+#ifndef CLAPACK_HELPER_H
+#define CLAPACK_HELPER_H
+
+// On wasm32, long is 32-bit
+typedef long clapack_int;
+
+// Wrapper functions that call CLAPACK with correct void return type
+void clapack_dgetrf_wrapper(
+    clapack_int *m,
+    clapack_int *n,
+    double *a,
+    clapack_int *lda,
+    clapack_int *ipiv,
+    clapack_int *info
+);
+
+void clapack_dgetri_wrapper(
+    clapack_int *n,
+    double *a,
+    clapack_int *lda,
+    clapack_int *ipiv,
+    double *work,
+    clapack_int *lwork,
+    clapack_int *info
+);
+
+#endif // CLAPACK_HELPER_H