Add Rich Felker's getsubopt, smaller then the glibc copied one

extra/Configs/Config.in

@@ -1086,6 +1086,14 @@ config UCLIBC_HAS_GNU_GETOPT
 
 	  Most people will answer Y.
 
+config UCLIBC_HAS_GNU_GETSUBOPT
+	bool "Support glibc getsubopt"
+	default y
+	help
+	  Answer Y if you want to include glibc getsubopt() instead of a
+	  smaller SUSv3 compatible getsubopt().
+
+	  Most people will answer Y.
 endmenu
 
 

libc/unistd/Makefile.in

@@ -24,6 +24,12 @@ else
 CSRC := $(filter-out getopt.c,$(CSRC))
 endif
 
+ifeq ($(UCLIBC_HAS_GNU_GETSUBOPT),y)
+CSRC := $(filter-out getsubopt-susv3.c,$(CSRC))
+else
+CSRC := $(filter-out getsubopt.c,$(CSRC))
+endif
+
 ifeq ($(UCLIBC_HAS_THREADS_NATIVE),y)
 CSRC := $(filter-out sleep.c,$(CSRC))
 endif

libc/unistd/getsubopt-susv3.c

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2006 Rich Felker <dalias@aerifal.cx>
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+libc_hidden_proto(strchr)
+libc_hidden_proto(strlen)
+libc_hidden_proto(strncmp)
+
+int getsubopt(char **opt, char *const *keys, char **val)
+{
+	char *s = *opt;
+	int i;
+
+	*val = NULL;
+	*opt = strchr(s, ',');
+	if (*opt) *(*opt)++ = 0;
+	else *opt = s + strlen(s);
+
+	for (i=0; keys[i]; i++) {
+		size_t l = strlen(keys[i]);
+		if (strncmp(keys[i], s, l)) continue;
+		if (s[l] == '=')
+			*val = s + l;
+		else if (s[l]) continue;
+		return i;
+	}
+	return -1;
+}