Fix the build with guile-3.0.0.

v2: Update configure.ac too.

Signed-off-by: orbea <orbea@riseup.net>

src/plugins/guile/weechat-guile-api.c

@@ -24,6 +24,8 @@
 
 #include <libguile.h>
 #include <time.h>
+#include <stdio.h>
+#include <string.h>
 
 #include "../weechat-plugin.h"
 #include "../plugin-script.h"

src/plugins/guile/weechat-guile.c

@@ -30,6 +30,8 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <libgen.h>
+#include <stdio.h>
+#include <string.h>
 
 #include "../weechat-plugin.h"
 #include "../plugin-script.h"