Index: InsightToolkit-5.1.0/Modules/ThirdParty/libLBFGS/src/CMakeLists.txt
===================================================================
--- InsightToolkit-5.1.0.orig/Modules/ThirdParty/libLBFGS/src/CMakeLists.txt
+++ InsightToolkit-5.1.0/Modules/ThirdParty/libLBFGS/src/CMakeLists.txt
@@ -17,6 +17,10 @@ set(ITK3P_INSTALL_RUNTIME_DIR "${ITKLIBL
 set(ITK3P_INSTALL_LIBRARY_DIR "${ITKLIBLBFGS_INSTALL_LIBRARY_DIR}")
 set(ITK3P_INSTALL_ARCHIVE_DIR "${ITKLIBLBFGS_INSTALL_ARCHIVE_DIR}")
 
+IF(UNIX)
+  TARGET_LINK_LIBRARIES(itklbfgs m)
+ENDIF(UNIX)
+
 INSTALL(TARGETS itklbfgs
   EXPORT ${ITK3P_INSTALL_EXPORT_NAME}
   RUNTIME DESTINATION ${ITK3P_INSTALL_RUNTIME_DIR} COMPONENT RuntimeLibraries