ENH: Integrate libLBFGS into our CMake build system

Fixes: InsightSoftwareConsortium#3135

Modules/Numerics/Optimizersv4/include/itkLBFGS2Optimizerv4.h

@@ -22,7 +22,7 @@
 #include "ITKOptimizersv4Export.h"
 #include <memory>
 
-#include "lbfgs.h"
+#include "itk_lbfgs.h"
 
 namespace itk
 {

Modules/ThirdParty/libLBFGS/CMakeLists.txt

@@ -13,9 +13,14 @@ set(ITKLIBLBFGS_THIRD_PARTY 1)
 #  set(ITKLIBLBFGS_NO_SRC 1)
 #else()
 
-set(ITKLIBLBFGS_INCLUDE_DIRS ${ITKLIBLBFGS_SOURCE_DIR}/include )
+set(ITKLIBLBFGS_INCLUDE_DIRS ${ITKLIBLBFGS_SOURCE_DIR}/src)
 set(ITKLIBLBFGS_LIBRARIES itklbfgs)
 
 #endif()
 
 itk_module_impl()
+
+install(FILES ${ITKLIBLBFGS_SOURCE_DIR}/src/itk_lbfgs.h
+  DESTINATION ${ITKLIBLBFGS_INSTALL_INCLUDE_DIR}
+  COMPONENT Development
+  )

Modules/ThirdParty/libLBFGS/src/CMakeLists.txt

@@ -1,25 +1,7 @@
-ADD_LIBRARY( itklbfgs
-  lbfgs.c
-)
-
-IF(ITK_LIBRARY_PROPERTIES)
-  SET_TARGET_PROPERTIES(itklbfgs PROPERTIES ${ITK_LIBRARY_PROPERTIES})
-ENDIF(ITK_LIBRARY_PROPERTIES)
-
 set(ITK3P_INSTALL_EXPORT_NAME "${ITKLIBLBFGS-targets}")
 set(ITK3P_INSTALL_INCLUDE_DIR "${ITKLIBLBFGS_INSTALL_INCLUDE_DIR}")
 set(ITK3P_INSTALL_RUNTIME_DIR "${ITKLIBLBFGS_INSTALL_RUNTIME_DIR}")
 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
-  LIBRARY DESTINATION ${ITK3P_INSTALL_LIBRARY_DIR} COMPONENT RuntimeLibraries
-  ARCHIVE DESTINATION ${ITK3P_INSTALL_ARCHIVE_DIR} COMPONENT Development)
-
+add_subdirectory(itklbfgs)
 itk_module_target(itklbfgs NO_INSTALL)

Modules/ThirdParty/libLBFGS/src/itk_lbfgs.h

@@ -0,0 +1,27 @@
+/*=========================================================================
+ *
+ *  Copyright NumFOCUS
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0.txt
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *=========================================================================*/
+/*=========================================================================
+ * Include file to wrap the internal ITK libLBFGS library header
+ *=========================================================================*/
+
+#ifndef itk_lbfgs_h
+#define itk_lbfgs_h
+
+#include <itklbfgs/include/lbfgs.h>
+
+#endif

Modules/ThirdParty/libLBFGS/src/itklbfgs/CMakeLists.txt

@@ -0,0 +1,20 @@
+add_library(itklbfgs lib/lbfgs.c)
+target_include_directories(itklbfgs PRIVATE include)
+
+if(ITK_LIBRARY_PROPERTIES)
+  set_target_properties(itklbfgs PROPERTIES ${ITK_LIBRARY_PROPERTIES})
+endif()
+
+if(UNIX)
+  target_link_libraries(itklbfgs m)
+endif()
+
+install(TARGETS itklbfgs
+  EXPORT ${ITK3P_INSTALL_EXPORT_NAME}
+  RUNTIME DESTINATION ${ITK3P_INSTALL_RUNTIME_DIR} COMPONENT RuntimeLibraries
+  LIBRARY DESTINATION ${ITK3P_INSTALL_LIBRARY_DIR} COMPONENT RuntimeLibraries
+  ARCHIVE DESTINATION ${ITK3P_INSTALL_ARCHIVE_DIR} COMPONENT Development)
+
+install(FILES
+  ${CMAKE_CURRENT_SOURCE_DIR}/include/lbfgs.h
+  DESTINATION ${ITK3P_INSTALL_INCLUDE_DIR}/itklbfgs/include)