make most headers private

src/mbgl/geometry/line_buffer.cpp

@@ -0,0 +1,23 @@
+#include <mbgl/geometry/line_buffer.hpp>
+#include <mbgl/platform/gl.hpp>
+
+#include <cmath>
+
+using namespace mbgl;
+
+size_t LineVertexBuffer::add(vertex_type x, vertex_type y, float ex, float ey, int8_t tx, int8_t ty, int32_t linesofar) {
+    size_t idx = index();
+    void *data = addElement();
+
+    int16_t *coords = static_cast<int16_t *>(data);
+    coords[0] = (x * 2) | tx;
+    coords[1] = (y * 2) | ty;
+
+    int8_t *extrude = static_cast<int8_t *>(data);
+    extrude[4] = std::round(extrudeScale * ex);
+    extrude[5] = std::round(extrudeScale * ey);
+
+    coords[3] = linesofar;
+
+    return idx;
+}