uname: make OS name configurable

A mailing list thread in September 2013 discussed changing the string
returned by the non-POSIX 'uname -o' option.  Nothing ever came of this
because there was no agreement as to what the string should be.

Make the string configurable so that people can decide for themselves.

Signed-off-by: Ron Yorston <rmy@frippery.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/uname.c b/coreutils/uname.c
index 1c6aa5f..fd677d2 100644
--- a/coreutils/uname.c
+++ b/coreutils/uname.c
@@ -74,7 +74,7 @@
 	struct utsname name;
 	char processor[sizeof(((struct utsname*)NULL)->machine)];
 	char platform[sizeof(((struct utsname*)NULL)->machine)];
-	char os[sizeof("GNU/Linux")];
+	char os[sizeof(CONFIG_UNAME_OSNAME)];
 } uname_info_t;
 
 static const char options[] ALIGN1 = "snrvmpioa";
@@ -141,7 +141,7 @@
 #endif
 	strcpy(uname_info.processor, unknown_str);
 	strcpy(uname_info.platform, unknown_str);
-	strcpy(uname_info.os, "GNU/Linux");
+	strcpy(uname_info.os, CONFIG_UNAME_OSNAME);
 #if 0
 	/* Fedora does something like this */
 	strcpy(uname_info.processor, uname_info.name.machine);