First steps towards removing glib dependencies

- remove the build flags and libraries from the Makefile / Configure.mk
- remove the glib types (gboolean, gchar, gint64, gint)
- comment out / hack around gettext
- replace the glib file helper functions
- replace g_ascii_strtod
- replace g_build_filename
- use environment variables instead of g_get_home_dir() & g_get_user_name()
- comment out GPS string parsing (uses glib utf8 macros)

This needs massive cleanup, but it's a snapshot of what I have right now, in
case people want to look at it.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

macos.c

@@ -169,8 +169,8 @@ const char *system_default_filename(void)
 	char *buffer;
 	int len;
 
-	home = g_get_home_dir();
-	user = g_get_user_name();
+	home = getenv("HOME");
+	user = getenv("LOGNAME");
 	len = strlen(home) + strlen(user) + 45;
 	buffer = malloc(len);
 	snprintf(buffer, len, "%s/Library/Application Support/Subsurface/%s.xml", home, user);
@@ -242,22 +242,22 @@ void subsurface_ui_setup(GtkSettings *settings, GtkWidget *menubar,
 }
 #endif /* UES_GTK_UI */
 
-void subsurface_command_line_init(gint *argc, gchar ***argv)
+void subsurface_command_line_init(int *argc, char ***argv)
 {
 	/* this is a no-op */
 }
 
-void subsurface_command_line_exit(gint *argc, gchar ***argv)
+void subsurface_command_line_exit(int *argc, char ***argv)
 {
 	/* this is a no-op */
 }
 
-gboolean subsurface_os_feature_available(os_feature_t f)
+int subsurface_os_feature_available(os_feature_t f)
 {
 	return TRUE;
 }
 
-gboolean subsurface_launch_for_uri(const char* uri)
+int subsurface_launch_for_uri(const char* uri)
 {
 	CFURLRef urlref = CFURLCreateWithBytes(NULL, uri, strlen(uri), kCFStringEncodingMacRoman, NULL);
 	OSStatus status = LSOpenCFURLRef(urlref, NULL);