Don't require get_executable_path

Author: augustss

src/runtime/eval.c

@@ -85,6 +85,10 @@ extern char **environ;          /* should probably be behind some WANT_ */
 #include "ffi_errno.c"
 #endif
 
+#if !defined(GET_EXECUTABLE_PATH)
+char *get_executable_path(void) { return NULL; }
+#endif
+
 #define NEED_INT64 (WANT_INT64 && WORD_SIZE < 64)
 
 #if WANT_LZ77

src/runtime/unix/extra.c

@@ -218,3 +218,4 @@ get_executable_path(void) {
     return NULL;
 #endif
 }
+#define GET_EXECUTABLE_PATH get_executable_path

src/runtime/windows/extra.c

@@ -181,3 +181,4 @@ get_executable_path(void) {
     free(wbuf);
     return utf8_buf;
 }
+#define GET_EXECUTABLE_PATH get_executable_path