eigen.patch

commit cf82186416d04ea5df2a397d8fe09dc78d40ca65
Author: Antonio Sánchez <cantonios@google.com>
Date:   Sat Mar 5 05:49:45 2022 +0000

    Adds new CMake Options for controlling build components.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index de1c23e91..0af36a53a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -477,6 +477,9 @@ if(EIGEN_BUILD_TESTING)
   add_subdirectory(failtest)
 endif()
 
+include(CMakeDetermineFortranCompiler)
+option(EIGEN_BUILD_BLAS "Toggles the building of the Eigen Blas library" ${CMAKE_Fortran_COMPILER})
+option(EIGEN_BUILD_LAPACK "Toggles the building of the included Eigen LAPACK library" ${CMAKE_Fortran_COMPILER})
 if(EIGEN_LEAVE_TEST_IN_ALL_TARGET)
   add_subdirectory(blas)
   add_subdirectory(lapack)
@@ -611,6 +614,8 @@ set_target_properties (eigen PROPERTIES EXPORT_NAME Eigen)
 
 install (TARGETS eigen EXPORT Eigen3Targets)
 
+option(EIGEN_BUILD_CMAKE_PACKAGE "Enables the creation of EigenConfig.cmake and related files" ON)
+if(EIGEN_BUILD_CMAKE_PACKAGE)
 configure_package_config_file (
   ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Eigen3Config.cmake.in
   ${CMAKE_CURRENT_BINARY_DIR}/Eigen3Config.cmake
@@ -655,6 +660,7 @@ install (FILES ${CMAKE_CURRENT_BINARY_DIR}/Eigen3Config.cmake
 # Add uninstall target
 add_custom_target ( uninstall
     COMMAND ${CMAKE_COMMAND} -P ${CMAKE_CURRENT_SOURCE_DIR}/cmake/EigenUninstall.cmake)
+endif()
 
 if (EIGEN_SPLIT_TESTSUITE)
   ei_split_testsuite("${EIGEN_SPLIT_TESTSUITE}")
diff --git a/blas/CMakeLists.txt b/blas/CMakeLists.txt
index 8d3cb86dc..c530957fb 100644
--- a/blas/CMakeLists.txt
+++ b/blas/CMakeLists.txt
@@ -1,6 +1,7 @@
 
 project(EigenBlas CXX)
 
+if(EIGEN_BUILD_BLAS)
 include(CheckLanguage)
 check_language(Fortran)
 if(CMAKE_Fortran_COMPILER)
@@ -59,4 +60,4 @@ if(EIGEN_BUILD_TESTING)
 endif()
 
 endif()
-
+endif()
diff --git a/lapack/CMakeLists.txt b/lapack/CMakeLists.txt
index c8ca64001..8d6d75401 100644
--- a/lapack/CMakeLists.txt
+++ b/lapack/CMakeLists.txt
@@ -1,5 +1,7 @@
 project(EigenLapack CXX)
 
+if(EIGEN_BUILD_LAPACK AND EIGEN_BUILD_BLAS)
+
 include(CheckLanguage)
 check_language(Fortran)
 if(CMAKE_Fortran_COMPILER)
@@ -457,3 +459,6 @@ if(EXISTS ${eigen_full_path_to_testing_lapack})
 
 endif()
 
+elseif(EIGEN_BUILD_LAPACK AND NOT EIGEN_BUILD_BLAS)
+ message(FATAL_ERROR "EIGEN_BUILD_LAPACK requires EIGEN_BUILD_BLAS")
+endif() #EIGEN_BUILD_LAPACK