chore: import upstream snapshot with attribution

tests/fixtures/sample.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_SIZE 256
+
+typedef struct {
+    int width;
+    int height;
+} Rectangle;
+
+static int validate(const char *input) {
+    return input != NULL && strlen(input) > 0;
+}
+
+char *process(const char *input) {
+    if (!validate(input)) {
+        return NULL;
+    }
+    char *result = malloc(MAX_SIZE);
+    strncpy(result, input, MAX_SIZE - 1);
+    return result;
+}
+
+Rectangle *make_rect(Rectangle *defaults) {
+    Rectangle *r = malloc(sizeof(Rectangle));
+    if (defaults) {
+        r->width = defaults->width;
+        r->height = defaults->height;
+    }
+    return r;
+}
+
+int main(int argc, char *argv[]) {
+    char *out = process("hello");
+    if (out) {
+        printf("%s\n", out);
+        free(out);
+    }
+    return 0;
+}