LibC: Add stubs for {get,free}ifaddrs

These are needed for our libuv port

userspace/libraries/LibC/CMakeLists.txt

@@ -12,6 +12,7 @@ set(LIBC_SOURCES
 	fenv.cpp
 	ftw.cpp
 	grp.cpp
+	ifaddrs.cpp
 	inttypes.cpp
 	langinfo.cpp
 	libgen.cpp

userspace/libraries/LibC/ifaddrs.cpp

@@ -0,0 +1,15 @@
+#include <ifaddrs.h>
+
+#include <BAN/Assert.h>
+
+int getifaddrs(struct ifaddrs** ifap)
+{
+	(void)ifap;
+	ASSERT_NOT_REACHED();
+}
+
+void freeifaddrs(struct ifaddrs*  ifa)
+{
+	(void)ifa;
+	ASSERT_NOT_REACHED();
+}

userspace/libraries/LibC/include/ifaddrs.h

@@ -0,0 +1,32 @@
+#ifndef _IFADDRS_H
+#define _IFADDRS_H 1
+
+// https://man7.org/linux/man-pages/man3/getifaddrs.3.html
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+
+struct ifaddrs
+{
+	struct ifaddrs*  ifa_next;    /* Next item in list */
+	char*            ifa_name;    /* Name of interface */
+	unsigned int     ifa_flags;   /* Flags from SIOCGIFFLAGS */
+	struct sockaddr* ifa_addr;    /* Address of interface */
+	struct sockaddr* ifa_netmask; /* Netmask of interface */
+	union {
+		struct sockaddr* ifu_broadaddr; /* Broadcast address of interface */
+		struct sockaddr* ifu_dstaddr;   /* Point-to-point destination address */
+	} ifa_ifu;
+	void*            ifa_data;    /* Address-specific data */
+};
+
+#define ifa_broadaddr ifa_ifu.ifu_broadaddr
+#define ifa_dstaddr   ifa_ifu.ifu_dstaddr
+
+int getifaddrs(struct ifaddrs **ifap);
+void freeifaddrs(struct ifaddrs *ifa);
+
+__END_DECLS
+
+#endif