-V now outputs compile-time configuration (fix #519)

ChangeLog

@@ -18,6 +18,12 @@ vNEXT:
 	inherit the listen sockets and block a new main
 	process from starting.
 
+	More configuration sanity checks (e.g. using regex
+	or proxyprotocol options if libraries are not compiled in)
+
+	-V now outputs compile-time options so it is
+	possible to know what is compiled in.
+
 v2.3.0:
 	Added `max_connections` setting to `listen` and
 	`protocol` configuration; see the

Makefile.in

@@ -22,11 +22,11 @@ MAN=sslh.8.gz	# man page name
 # itself
 
 ifneq ($(strip $(ENABLE_SANITIZER)),)
-    CFLAGS_SAN=-fsanitize=address -fsanitize=leak -fsanitize=undefined -fsanitize=alignment
+    CFLAGS_SAN=-DENABLE_SANITIZER -fsanitize=address -fsanitize=leak -fsanitize=undefined -fsanitize=alignment
 endif
 
 ifneq ($(strip $(COV_TEST)),)
-    CFLAGS_COV=-fprofile-arcs -ftest-coverage
+    CFLAGS_COV=-DCOV_TEST -fprofile-arcs -ftest-coverage
 endif
 
 CC ?= gcc

sslh-main.c

@@ -348,6 +348,41 @@ void close_std(void)
     }
 }
 
+static void print_version(void)
+{
+    printf("%s %s\n", server_type, VERSION);
+#ifdef ENABLE_SANITIZER
+    printf("ENABLE_SANITIZER\n");
+#endif
+#ifdef ENABLE_REGEX
+    printf("ENABLE_REGEX\n");
+#endif
+#ifdef LIBCONFIG
+    printf("LIBCONFIG\n");
+#endif
+#ifdef SYSTEMD
+    printf("SYSTEMD\n");
+#endif
+#ifdef COV_TEST
+    printf("COV_TEST\n");
+#endif
+#ifdef HAVE_LIBWRAP
+    printf("HAVE_LIBWRAP\n");
+#endif
+#ifdef HAVE_LANDLOCK
+    printf("HAVE_LANDLOCK\n");
+#endif
+#ifdef HAVE_PROXYPROTOCOL
+    printf("HAVE_PROXYPROTOCOL\n");
+#endif
+#ifdef HAVE_LIBCAP
+    printf("HAVE_LIBCAP\n");
+#endif
+#ifdef HAVE_LIBBSD
+    printf("HAVE_LIBBSD\n");
+#endif
+}
+
 int main(int argc, char *argv[], char* envp[])
 {
    int res, num_addr_listen;
@@ -363,7 +398,7 @@ int main(int argc, char *argv[], char* envp[])
    config_finish(&cfg);
 
    if (cfg.version) {
-       printf("%s %s\n", server_type, VERSION);
+       print_version();
        exit(0);
    }