Fix Ctrl+D on FreeBSD

This was broken by the macOS fix because apparently, editline acts
differently on those platforms.

I have tested that Linux, macOS, and FreeBSD all work with this one,
both SIGWINCH and Ctrl+D. Well, Ctrl+D doesn't work on macOS, but that
is actually a limitation I *can't* get around.

Fixes FreeBSD being broken by 56bb182.

Signed-off-by: Gavin D. Howard <gavin@gavinhoward.com>

Author: gavinhoward

include/history.h

@@ -120,6 +120,30 @@ typedef struct BcHistory
 extern const char bc_history_editrc[];
 extern const size_t bc_history_editrc_len;
 
+#ifdef __APPLE__
+
+/**
+ * Returns true if the line is a valid line, false otherwise.
+ * @param line  The line.
+ * @param len   The length of the line.
+ * @return      True if the line is valid, false otherwise.
+ */
+#define BC_HISTORY_INVALID_LINE(line, len) \
+	((line) == NULL && ((len) == -1 || errno == EINTR))
+
+#else // __APPLE__
+
+/**
+ * Returns true if the line is a valid line, false otherwise.
+ * @param line  The line.
+ * @param len   The length of the line.
+ * @return      True if the line is valid, false otherwise.
+ */
+#define BC_HISTORY_INVALID_LINE(line, len) \
+	((line) == NULL && (len) == -1 && errno == EINTR)
+
+#endif // __APPLE__
+
 #else // BC_ENABLE_EDITLINE
 
 #if BC_ENABLE_READLINE

src/history.c

@@ -264,7 +264,18 @@ bc_history_line(BcHistory* h, BcVec* vec, const char* prompt)
 	errno = EINTR;
 
 	// Get the line.
-	while (line == NULL && (len == -1 || errno == EINTR))
+	//
+	// XXX: Why have a macro here? Because macOS needs to be special. Honestly,
+	// it's starting to feel special like Windows at this point. Anyway, the
+	// second SIGWINCH signal of multiple will  return a valid line length on
+	// macOS, so we need to allow for that on macOS. However, FreeBSD's editline
+	// is different and will mess up the terminal if we do it that way.
+	//
+	// There is one limitation with this, however: Ctrl+D won't work on macOS.
+	// But it's because of macOS that this problem exists, and I can't really do
+	// anything about it. So macOS should fix their broken editline; once they
+	// do, I'll fix Ctrl+D on macOS.
+	while (BC_HISTORY_INVALID_LINE(line, len))
 	{
 		line = el_gets(h->el, &len);
 		bc_history_use_prompt = false;