diff --git a/common/lc_global.h b/common/lc_global.h
index 1ddc70fc..f523be5a 100644
--- a/common/lc_global.h
+++ b/common/lc_global.h
@@ -11,6 +11,10 @@
 #include <QPrinter>
 #include <array>
 
+#ifndef Q_FALLTHROUGH
+#define Q_FALLTHROUGH (void)0
+#endif
+
 #if !defined(EGL_VERSION_1_0) && !defined(GL_ES_VERSION_2_0) && !defined(GL_ES_VERSION_3_0) && !defined(QT_OPENGL_ES)
 #undef GL_LINES_ADJACENCY_EXT
 #undef GL_LINE_STRIP_ADJACENCY_EXT
diff --git a/common/lc_library.cpp b/common/lc_library.cpp
index 0653800f..82b7574b 100644
--- a/common/lc_library.cpp
+++ b/common/lc_library.cpp
@@ -921,7 +921,9 @@ bool lcPiecesLibrary::ReadArchiveCacheFile(const QString& FileName, lcMemFile& C
 			{
 			case Z_NEED_DICT:
 				ret = Z_DATA_ERROR;
+				Q_FALLTHROUGH();
 			case Z_DATA_ERROR:
+				Q_FALLTHROUGH();
 			case Z_MEM_ERROR:
 				(void)inflateEnd(&strm);
 				return ret;
@@ -2715,6 +2717,7 @@ void lcLibraryMeshData::AddLine(lcMeshDataType MeshDataType, int LineType, quint
 				Section->mIndices.Add(Indices[2]);
 			}
 		}
+		Q_FALLTHROUGH();
 
 	case 3:
 		if (Indices[0] != Indices[1] && Indices[0] != Indices[2] && Indices[1] != Indices[2])
@@ -2911,6 +2914,7 @@ void lcLibraryMeshData::AddTexturedLine(lcMeshDataType MeshDataType, int LineTyp
 				Section->mIndices.Add(Indices[2]);
 			}
 		}
+		Q_FALLTHROUGH();
 	case 3:
 		if (Indices[0] != Indices[1] && Indices[0] != Indices[2] && Indices[1] != Indices[2])
 		{