Moved read_file to a general base library

asm/main.cpp

@@ -20,28 +20,11 @@
 
 #include <lib/inst.h>
 
+#include "./base.hpp"
 #include "./lexer.hpp"
 
 using std::pair, std::string, std::string_view, std::vector;
 
-std::optional<string> read_file(const char *filename)
-{
-  FILE *fp = fopen(filename, "rb");
-  if (fp)
-  {
-    string contents;
-    fseek(fp, 0, SEEK_END);
-    contents.resize(ftell(fp));
-    rewind(fp);
-    fread(&contents[0], 1, contents.size(), fp);
-    fclose(fp);
-
-    return contents;
-  }
-  else
-    return std::nullopt;
-}
-
 void usage(const char *program_name, FILE *fp)
 {
   fprintf(fp,