Add a "fork" of musl as //fusl.

fusl/src/env/putenv.c

Index: fusl/src/env/putenv.c
diff --git a/fusl/src/env/putenv.c b/fusl/src/env/putenv.c
new file mode 100644
index 0000000000000000000000000000000000000000..4042869b500f1866e111918f121ba3d08d962287
--- /dev/null
+++ b/fusl/src/env/putenv.c
@@ -0,0 +1,57 @@
+#include <stdlib.h>
+#include <string.h>
+
+extern char **__environ;
+char **__env_map;
+
+int __putenv(char *s, int a)
+{
+	int i=0, j=0;
+	char *z = strchr(s, '=');
+	char **newenv = 0;
+	char **newmap = 0;
+	static char **oldenv;
+
+	if (!z) return unsetenv(s);
+	if (z==s) return -1;
+	for (; __environ[i] && memcmp(s, __environ[i], z-s+1); i++);
+	if (a) {
+		if (!__env_map) {
+			__env_map = calloc(2, sizeof(char *));
+			if (__env_map) __env_map[0] = s;
+		} else {
+			for (; __env_map[j] && __env_map[j] != __environ[i]; j++);
+			if (!__env_map[j]) {
+				newmap = realloc(__env_map, sizeof(char *)*(j+2));
+				if (newmap) {
+					__env_map = newmap;
+					__env_map[j] = s;
+					__env_map[j+1] = NULL;
+				}
+			} else {
+				free(__env_map[j]);
+			}
+		}
+	}
+	if (!__environ[i]) {
+		newenv = malloc(sizeof(char *)*(i+2));
+		if (!newenv) {
+			if (a && __env_map) __env_map[j] = 0;
+			return -1;
+		}
+		memcpy(newenv, __environ, sizeof(char *)*i);
+		newenv[i] = s;
+		newenv[i+1] = 0;
+		__environ = newenv;
+		free(oldenv);
+		oldenv = __environ;
+	}
+
+	__environ[i] = s;
+	return 0;
+}
+
+int putenv(char *s)
+{
+	return __putenv(s, 0);
+}