ports/posix: Allow building with -static, skipping readline

With this patch,

	$ make STATIC=1

will build the posix snek port as a static executable.

It seems that libreadline doesn't like to be used with static
executables because it wants to dlopen some helper libaries.  To work
around this, just skip readline in this case.

Signed-off-by: Keith Packard <keithp@keithp.com>

ports/posix/Makefile

@@ -29,9 +29,18 @@ include $(SNEK_ROOT)/snek-install.defs
 
 OPT?=-O3
 
-CFLAGS+=-DSNEK_MEM_INCLUDE_NAME $(OPT) -g -I. $(SNEK_CFLAGS) -Werror $(CPPFLAGS) $(CFLAGS_POSIX)
+STATIC?=0
 
-LIBS=-lreadline -lm
+ifeq ($(STATIC),0)
+LIBS_READLINE=-lreadline
+CFLAGS_READLINE=-DUSE_READLINE
+else
+LIBS_STATIC=-static
+endif
+
+CFLAGS+=-DSNEK_MEM_INCLUDE_NAME $(CFLAGS_READLINE) $(OPT) -g -I. $(SNEK_CFLAGS) -Werror $(CPPFLAGS) $(CFLAGS_POSIX)
+
+LIBS=$(LIBS_STATIC) $(LIBS_READLINE) -lm
 
 all: snek snek.desktop
 

ports/posix/snek-main.c

@@ -14,8 +14,10 @@
 
 #include "snek.h"
 #include <getopt.h>
+#ifdef USE_READLINE
 #include <readline/readline.h>
 #include <readline/history.h>
+#endif
 #include <signal.h>
 
 FILE	*snek_posix_input;
@@ -34,6 +36,23 @@ usage (char *program, int val)
 	exit(val);
 }
 
+#ifdef USE_READLINE
+#define snek_readline(p) readline(p)
+#define snek_add_history(p) add_history(p)
+#define snek_free_line(p) free(p)
+#else
+static char *
+snek_readline(char *prompt)
+{
+	static char	line[256];
+	fputs(prompt, stdout);
+	fflush(stdout);
+	return fgets(line, sizeof(line), stdin);
+}
+#define snek_add_history(p)
+#define snek_free_line(p)
+#endif
+
 static int
 snek_getc_interactive(void)
 {
@@ -45,16 +64,16 @@ snek_getc_interactive(void)
 		char *prompt = "> ";
 		if (snek_parse_middle)
 			prompt = "+ ";
-		line_base = readline (prompt);
+		line_base = snek_readline (prompt);
 		line = line_base;
 		if (!line)
 			return EOF;
-		add_history (line_base);
+		snek_add_history (line_base);
 	}
 	c = (*line++) & 0xff;
 	if (!c) {
 		c = '\n';
-		free (line_base);
+		snek_free_line (line_base);
 		line = 0;
 	}
 	return c;