diff -up megaglest-3.13.0/source/shared_lib/CMakeLists.txt.orig megaglest-3.13.0/source/shared_lib/CMakeLists.txt
--- megaglest-3.13.0/source/shared_lib/CMakeLists.txt.orig 2019-09-24 15:38:49.867482131 -0300
+++ megaglest-3.13.0/source/shared_lib/CMakeLists.txt 2019-09-24 15:39:00.045556832 -0300
@@ -109,7 +109,7 @@ IF(BUILD_MEGAGLEST_MODEL_VIEWER OR BUILD
FIND_PACKAGE(OpenGL REQUIRED)
INCLUDE_DIRECTORIES(${OPENGL_INCLUDE_DIR})
IF(UNIX)
- SET(EXTERNAL_LIBS ${EXTERNAL_LIBS} ${OPENGL_LIBRARY})
+ SET(EXTERNAL_LIBS ${EXTERNAL_LIBS} ${OPENGL_LIBRARY} -lX11)
ENDIF()
FIND_PACKAGE(X11 REQUIRED)