Fix #7 by making g_ functions work under Linux.

Author: rhx

Sources/CGLib/glib_bridging.h

@@ -1,3 +1,8 @@
+#ifdef __linux__
+#include <sys/types.h>
+#include <utime.h>
+extern int g_open (const char *, int, ...) __nonnull ((1));
+#endif
 #define __GLIB_H_INSIDE__
 #include <glib/gversion.h>
 #include <glib/gversionmacros.h>

Sources/GLib/GLib.swift

@@ -318,6 +318,7 @@ public func g_mkdir(_ path: UnsafePointer<CChar>, _ mode: gint) -> CInt {
     return mkdir(path, mode_t(mode))
 }
 
+#if os(macOS)
 /// Open a file.
 ///
 /// This function is a wrapper around the `open()` system call,
@@ -332,6 +333,7 @@ public func g_mkdir(_ path: UnsafePointer<CChar>, _ mode: gint) -> CInt {
 public func g_open(_ path: UnsafePointer<CChar>, _ flags: CInt, _ mode: gint = 0) -> CInt {
     return open(path, flags, mode_t(mode))
 }
+#endif
 
 /// Remove a filesystem object.
 ///