Complete Phase 1: Build KiCad with optional dependencies disabled

Add CMake override modules, stub implementations, and patches to build
KiCad without CURL, libgit2, OpenCASCADE, and ngspice dependencies.

- cmake/: Find modules that provide stub targets when deps disabled
- stubs/include/: Header stubs for curl, git2, ngspice, OCC
- stubs/src/: Implementation stubs for disabled features
- patches/: Consolidated patch for KiCad source modifications
- scripts/: Build helper scripts

Verified full native build on macOS with all optional deps disabled.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

stubs/include/curl/curl.h

@@ -0,0 +1,149 @@
+/*
+ * KiCad Wasm Port - CURL Stub Header
+ *
+ * This is a minimal stub header for when KICAD_USE_CURL=0.
+ * It provides just enough type definitions to let the code compile
+ * without the actual libcurl library.
+ */
+
+#ifndef KICAD_WASM_CURL_STUB_H
+#define KICAD_WASM_CURL_STUB_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* CURL handle type */
+typedef void CURL;
+
+/* CURL multi handle */
+typedef void CURLM;
+
+/* CURL share handle */
+typedef void CURLSH;
+
+/* Linked list for headers */
+struct curl_slist {
+    char *data;
+    struct curl_slist *next;
+};
+
+/* Error codes */
+typedef enum {
+    CURLE_OK = 0,
+    CURLE_UNSUPPORTED_PROTOCOL,
+    CURLE_FAILED_INIT,
+    CURLE_URL_MALFORMAT,
+    CURLE_NOT_BUILT_IN,
+    CURLE_COULDNT_RESOLVE_PROXY,
+    CURLE_COULDNT_RESOLVE_HOST,
+    CURLE_COULDNT_CONNECT,
+    CURLE_REMOTE_ACCESS_DENIED = 9,
+    CURLE_HTTP_RETURNED_ERROR = 22,
+    CURLE_WRITE_ERROR = 23,
+    CURLE_READ_ERROR = 26,
+    CURLE_OUT_OF_MEMORY = 27,
+    CURLE_OPERATION_TIMEDOUT = 28,
+    CURLE_SSL_CONNECT_ERROR = 35,
+    CURLE_ABORTED_BY_CALLBACK = 42,
+    CURLE_GOT_NOTHING = 52,
+    CURLE_SSL_ENGINE_NOTFOUND = 53,
+    CURLE_SSL_ENGINE_SETFAILED = 54,
+    CURLE_SEND_ERROR = 55,
+    CURLE_RECV_ERROR = 56,
+    CURLE_SSL_CERTPROBLEM = 58,
+    CURLE_SSL_CIPHER = 59,
+    CURLE_PEER_FAILED_VERIFICATION = 60,
+    CURLE_BAD_CONTENT_ENCODING = 61,
+    CURLE_FILESIZE_EXCEEDED = 63,
+    CURLE_SEND_FAIL_REWIND = 65,
+    CURLE_LOGIN_DENIED = 67,
+    CURLE_REMOTE_DISK_FULL = 70,
+    CURLE_REMOTE_FILE_EXISTS = 73,
+    CURLE_SSH = 79,
+    CURLE_AGAIN = 81,
+    CURLE_SSL_CRL_BADFILE = 82,
+    CURLE_SSL_ISSUER_ERROR = 83,
+    CURLE_CHUNK_FAILED = 88,
+    CURLE_NO_CONNECTION_AVAILABLE = 89,
+    CURLE_SSL_PINNEDPUBKEYNOTMATCH = 90,
+    CURLE_SSL_INVALIDCERTSTATUS = 91,
+    CURLE_HTTP2_STREAM = 92,
+    CURL_LAST
+} CURLcode;
+
+/* CURL options (minimal subset) */
+typedef enum {
+    CURLOPT_URL = 10002,
+    CURLOPT_WRITEFUNCTION = 20011,
+    CURLOPT_WRITEDATA = 10001,
+    CURLOPT_USERAGENT = 10018,
+    CURLOPT_HTTPHEADER = 10023,
+    CURLOPT_POSTFIELDS = 10015,
+    CURLOPT_FOLLOWLOCATION = 52,
+    CURLOPT_SSL_VERIFYPEER = 64,
+    CURLOPT_SSL_VERIFYHOST = 81,
+    CURLOPT_TIMEOUT = 13,
+    CURLOPT_CONNECTTIMEOUT = 78,
+    CURLOPT_NOPROGRESS = 43,
+    CURLOPT_PROGRESSFUNCTION = 20056,
+    CURLOPT_PROGRESSDATA = 10057,
+    CURLOPT_XFERINFOFUNCTION = 20219,
+    CURLOPT_XFERINFODATA = 10057
+} CURLoption;
+
+/* CURL info types */
+typedef enum {
+    CURLINFO_RESPONSE_CODE = 0x200002,
+    CURLINFO_CONTENT_LENGTH_DOWNLOAD = 0x300015,
+    CURLINFO_SIZE_DOWNLOAD = 0x300008
+} CURLINFO;
+
+/* Global flags */
+#define CURL_GLOBAL_DEFAULT 3
+#define CURL_GLOBAL_SSL 1
+#define CURL_GLOBAL_WIN32 2
+#define CURL_GLOBAL_ALL 3
+
+/* Stub function declarations - all return error or NULL */
+static inline CURL* curl_easy_init(void) { return NULL; }
+static inline void curl_easy_cleanup(CURL* curl) { (void)curl; }
+static inline CURLcode curl_easy_setopt(CURL* curl, CURLoption option, ...) {
+    (void)curl; (void)option;
+    return CURLE_NOT_BUILT_IN;
+}
+static inline CURLcode curl_easy_perform(CURL* curl) {
+    (void)curl;
+    return CURLE_NOT_BUILT_IN;
+}
+static inline CURLcode curl_easy_getinfo(CURL* curl, CURLINFO info, ...) {
+    (void)curl; (void)info;
+    return CURLE_NOT_BUILT_IN;
+}
+static inline const char* curl_easy_strerror(CURLcode error) {
+    (void)error;
+    return "CURL support not built in";
+}
+static inline char* curl_easy_escape(CURL* curl, const char* string, int length) {
+    (void)curl; (void)string; (void)length;
+    return NULL;
+}
+static inline void curl_free(void* p) { (void)p; }
+
+static inline struct curl_slist* curl_slist_append(struct curl_slist* list, const char* string) {
+    (void)list; (void)string;
+    return NULL;
+}
+static inline void curl_slist_free_all(struct curl_slist* list) { (void)list; }
+
+static inline CURLcode curl_global_init(long flags) { (void)flags; return CURLE_OK; }
+static inline void curl_global_cleanup(void) { }
+static inline const char* curl_version(void) { return "curl-stub/0.0 (KICAD_USE_CURL=0)"; }
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* KICAD_WASM_CURL_STUB_H */

stubs/include/curl/easy.h

@@ -0,0 +1,12 @@
+/*
+ * KiCad Wasm Port - CURL Easy API Stub Header
+ *
+ * This stub is empty because curl.h includes all the easy API.
+ */
+
+#ifndef KICAD_WASM_CURL_EASY_STUB_H
+#define KICAD_WASM_CURL_EASY_STUB_H
+
+#include "curl.h"
+
+#endif /* KICAD_WASM_CURL_EASY_STUB_H */