fix: add strings terminators

src/compiler/fzl_writer.c

@@ -2,7 +2,6 @@
 #include <compiler/fzl_writer.h>
 #include <compiler/internals/writer.h>
 #include <compiler/utils/fzl_const_pool.h>
-#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -14,11 +13,11 @@ char wrlast_err[256];
 fzl_writer_t *fzl_mkwriter(const char *filepath)
 {
   if (strlen(filepath) < 1)
-    return NULL;
+    return nullptr;
 
   fzl_writer_t *writer = malloc(sizeof(fzl_writer_t));
   if (!writer)
-    return NULL;
+    return nullptr;
 
   writer->filepath = filepath;
 
@@ -38,7 +37,7 @@ int fzl_write(fzl_writer_t *writer, fzl_gen_t *gen)
     return -1;
   }
 
-  const char hdr[5] = {'F', 'Z', 'L', 0x0, 0x2};
+  constexpr char hdr[5] = {'F', 'Z', 'L', 0x0, 0x2};
   fwrite(hdr, sizeof(char), 5, fd);
   fwrite(&gen->consts->size, sizeof(uint16_t), 1, fd);
   fwrite(&gen->extern_libs_count, sizeof(uint16_t), 1, fd);