document tiny flag; have it use flto on clang

doc/TINYCONFIG.md

@@ -0,0 +1,8 @@
+# Tiny Config
+
+Milsko's configure script supports the `--tiny` option for building the tiniest possible Milsko library (~400kb as of writing). Currently, what it does is:
+
+- Add `-Oz` to the cflags
+- (clang only) add `-flto=thin` to the cflags and linker flags
+- Build stb-image with `STB_IMAGE_STATIC` (this is why you get warnings with stb_image when you use it)
+- Disable the Wayland backend

pl/rules.pl

@@ -3,6 +3,10 @@ new_object("src/*.c");
 my $gl_libs = "";
 if (param_get("tiny")) {
     add_cflags("-Oz");
+    if(defined($ENV{CC}) && grep(/^clang$/, $ENV{CC})) {
+        add_libs("-flto=thin");
+        add_cflags("-flto=thin");
+    }
 }
 if (param_get("classic-theme")) {
     add_cflags("-DUSE_CLASSIC_THEME");