Revert "Remove unneeded quotes when using #error"

This reverts commit 9740d571ddd138f8344ba0975b11bc29621bc618.

New occurrences of #error are also affected by this commit.

1 files changed, 1 insertions, 1 deletions

diff --git a/shell.c b/shell.c
index e91cb90..eb42475 100644
--- a/shell.c
+++ b/shell.c
@@ -113,7 +113,7 @@ struct shell_line {
 #define SHELL_HISTORY_SIZE 21
 
 #if SHELL_HISTORY_SIZE == 0
-#error shell history size must be non-zero
+#error "shell history size must be non-zero"
 #endif /* SHELL_HISTORY_SIZE == 0 */
 
 /*