feat: embed version string and git commit hash (#1008)

version.cpp

@@ -0,0 +1,20 @@
+#include "stable-diffusion.h"
+
+#ifndef SDCPP_BUILD_COMMIT
+#define SDCPP_BUILD_COMMIT unknown
+#endif
+
+#ifndef SDCPP_BUILD_VERSION
+#define SDCPP_BUILD_VERSION unknown
+#endif
+
+#define STRINGIZE2(x) #x
+#define STRINGIZE(x) STRINGIZE2(x)
+
+const char* sd_commit(void) {
+    return STRINGIZE(SDCPP_BUILD_COMMIT);
+}
+
+const char* sd_version(void) {
+    return STRINGIZE(SDCPP_BUILD_VERSION);
+}