https://bugs.gentoo.org/969771
Use modern booleans instead of redefining them.
Also do an boost api change for extensions as
it was done in different patch.
--- a/backends/frotz/dfrotz/common/frotz.h
+++ b/backends/frotz/dfrotz/common/frotz.h
@@ -13,14 +13,14 @@
 
 #ifndef __UNIX_PORT_FILE
 #include <signal.h>
-typedef int bool;
+#include <stdbool.h>
 
 #ifndef TRUE
-#define TRUE 1
+#define TRUE true
 #endif
 
 #ifndef FALSE
-#define FALSE 0
+#define FALSE false
 #endif
 
 #endif /* __UNIX_PORT_FILE */
@@ -594,12 +594,12 @@
 void 	os_init_screen (void);
 void 	os_more_prompt (void);
 int  	os_peek_colour (void);
-int  	os_picture_data (int, int *, int *);
+bool  	os_picture_data (int, int *, int *);
 void 	os_prepare_sample (int);
 void 	os_process_arguments (int, char *[]);
 int	os_random_seed (void);
 int  	os_read_file_name (char *, const char *, int);
-zchar	os_read_key (int, int);
+zchar	os_read_key (int, bool);
 zchar	os_read_line (int, zchar *, int, int, int);
 void 	os_reset_screen (void);
 void 	os_restart_game (int);
--- a/backends/frotz/main.cpp
+++ b/backends/frotz/main.cpp
@@ -234,7 +234,7 @@
 			path p(".");
 			directory_iterator end_itr;
 			for (directory_iterator itr(p); itr != end_itr; ++itr) {
-				if (extension(itr->path()) == ".z5") {
+				if (itr->path().extension().string() == ".z5") {
 #if BOOST_FILESYSTEM_VERSION == 3
 					games.push_back(itr->path().filename().string());
 #else