use lv2.h provided at root of /usr/include

fixes ubuntu issues

.gitignore

@@ -1,3 +1,4 @@
 zig-cache/
 *.mp3
 *.wav
+build_runner.zig

build.zig

@@ -19,6 +19,7 @@ fn setupLinks(step: *builds.LibExeObjStep) void {
         "/usr/include/lilv-0/lilv",
         "/usr/include/lilv-0",
     };
+
     var found_any_lilv = false;
 
     for (possible_lilv_include_dirs) |possible_lilv_dir| {

src/lv2_helpers.zig

@@ -4,7 +4,7 @@ const plugin = @import("plugin.zig");
 pub const c = @cImport({
     @cInclude("sndfile.h");
     @cInclude("lilv/lilv.h");
-    @cInclude("lv2/core/lv2.h");
+    @cInclude("lv2.h");
 });
 
 pub fn Lv2Core(comptime ns: []const u8) []const u8 {