bin: Clang warning fixes.

* Functions that call exit() should return void
 * char* -> const char*
 * main returns int, not bool.

src/bin/checkfs.cpp

@@ -98,7 +98,7 @@ main(int argc, char** argv)
 	if (status != B_OK) {
 		fprintf(stderr, "%s: Could not prepare the device for modifications: "
 			"%s\n", kProgramName, strerror(status));
-		return false;
+		return 1;
 	}
 
 	// Check if the partition supports repairing

src/bin/eject.cpp

@@ -59,7 +59,7 @@ private:
 };
 
 
-static int usage(char *prog)
+static int usage(const char *prog)
 {
 	printf("usage: eject [-q|-l|-s|-b|-u] /dev/disk/.../raw\n");
 //	printf("usage: eject [-q|-l|-s|-b|-u] [scsi|ide|/dev/disk/.../raw]\n");

src/bin/setversion.cpp

@@ -134,7 +134,7 @@ errorToString(BString& output, status_t error, const char *appName = NULL)
 }
 
 
-static int
+static void
 errorOut(status_t error, const char *appName = NULL, bool showUsage = true)
 {
 	BString output;
@@ -304,9 +304,9 @@ main(int argc, char *argv[])
 {
 	if (argc < 3) {
 		if (argc < 2)
-			return errorOut(e_app_sys_switch);
+			errorOut(e_app_sys_switch);
 
-		return errorOut(e_specify_version);
+		errorOut(e_specify_version);
 	}
 
 	// reset version infos