vcpkg/ports/ceres/0004_fix_find_eigen.patch

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7033de0..5235baa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -209,40 +209,40 @@ endif (IOS)
 unset(CERES_COMPILE_OPTIONS)
 
 # Eigen.
-find_package(Eigen REQUIRED)
-if (EIGEN_FOUND)
-  message("-- Found Eigen version ${EIGEN_VERSION}: ${EIGEN_INCLUDE_DIRS}")
-  if (EIGEN_VERSION VERSION_LESS 3.1.0)
+find_package(Eigen3 REQUIRED)
+if (EIGEN3_FOUND)
+  message(STATUS "Found Eigen version ${EIGEN3_VERSION_STRING}: ${EIGEN3_INCLUDE_DIRS}")
+  if (EIGEN3_VERSION_STRING VERSION_LESS 3.1.0)
     message(FATAL_ERROR "-- Ceres requires Eigen version >= 3.1.0 in order "
       "that Eigen/SparseCore be available, detected version of Eigen is: "
-      "${EIGEN_VERSION}")
-  endif (EIGEN_VERSION VERSION_LESS 3.1.0)
+      "${EIGEN3_VERSION_STRING}")
+  endif (EIGEN3_VERSION_STRING VERSION_LESS 3.1.0)
 
   if (CMAKE_SYSTEM_PROCESSOR MATCHES "^(aarch64.*|AARCH64.*)" AND
-      EIGEN_VERSION VERSION_LESS 3.3.4)
+      EIGEN3_VERSION_STRING VERSION_LESS 3.3.4)
     # As per issue #289: https://github.com/ceres-solver/ceres-solver/issues/289
     # the bundle_adjustment_test will fail for Eigen < 3.3.4 on aarch64.
     message(FATAL_ERROR "-- Ceres requires Eigen version >= 3.3.4 on aarch64. "
-      "Detected version of Eigen is: ${EIGEN_VERSION}.")
+      "Detected version of Eigen is: ${EIGEN3_VERSION_STRING}.")
   endif()
 
   if (EIGENSPARSE)
-    message("-- Enabling use of Eigen as a sparse linear algebra library.")
+    message(STATUS "Enabling use of Eigen as a sparse linear algebra library.")
     list(APPEND CERES_COMPILE_OPTIONS CERES_USE_EIGEN_SPARSE)
-    if (EIGEN_VERSION VERSION_LESS 3.2.2)
+    if (EIGEN3_VERSION_STRING VERSION_LESS 3.2.2)
       message("   WARNING:")
       message("")
-      message("   Your version of Eigen (${EIGEN_VERSION}) is older than ")
+      message("   Your version of Eigen (${EIGEN3_VERSION_STRING}) is older than ")
       message("   version 3.2.2.  The performance of SPARSE_NORMAL_CHOLESKY ")
       message("   and SPARSE_SCHUR linear solvers will suffer.")
-    endif (EIGEN_VERSION VERSION_LESS 3.2.2)
+    endif (EIGEN3_VERSION_STRING VERSION_LESS 3.2.2)
   else (EIGENSPARSE)
     message("-- Disabling use of Eigen as a sparse linear algebra library.")
     message("   This does not affect the covariance estimation algorithm ")
     message("   which can still use the EIGEN_SPARSE_QR algorithm.")
     add_definitions(-DEIGEN_MPL2_ONLY)
   endif (EIGENSPARSE)
-endif (EIGEN_FOUND)
+endif (EIGEN3_FOUND)
 
 if (LAPACK)
   find_package(LAPACK QUIET)
@@ -562,7 +562,7 @@ include_directories(
 # Note that this is *not* propagated to clients, ie CERES_INCLUDE_DIRS
 # used by clients after find_package(Ceres) does not identify Eigen as
 # as system headers.
-include_directories(SYSTEM ${EIGEN_INCLUDE_DIRS})
+include_directories(${EIGEN3_INCLUDE_DIRS})
 
 if (SUITESPARSE)
   include_directories(${SUITESPARSE_INCLUDE_DIRS})
diff --git a/cmake/CeresConfig.cmake.in b/cmake/CeresConfig.cmake.in
index c4ed71f..b3d6a17 100644
--- a/cmake/CeresConfig.cmake.in
+++ b/cmake/CeresConfig.cmake.in
@@ -202,39 +202,39 @@ set(CERES_VERSION @CERES_VERSION@ )
 
 # Eigen.
 # Flag set during configuration and build of Ceres.
-set(CERES_EIGEN_VERSION @EIGEN_VERSION@)
+set(CERES_EIGEN_VERSION @EIGEN3_VERSION_STRING@)
 set(EIGEN_WAS_BUILT_WITH_CMAKE @FOUND_INSTALLED_EIGEN_CMAKE_CONFIGURATION@)
 # Append the locations of Eigen when Ceres was built to the search path hints.
 if (EIGEN_WAS_BUILT_WITH_CMAKE)
   set(Eigen3_DIR @Eigen3_DIR@)
   set(EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION TRUE)
 else()
-  list(APPEND EIGEN_INCLUDE_DIR_HINTS @EIGEN_INCLUDE_DIR@)
+  list(APPEND EIGEN_INCLUDE_DIR_HINTS @EIGEN3_INCLUDE_DIR@)
 endif()
 # Search quietly to control the timing of the error message if not found. The
 # search should be for an exact match, but for usability reasons do a soft
 # match and reject with an explanation below.
-find_package(Eigen ${CERES_EIGEN_VERSION} QUIET)
-if (EIGEN_FOUND)
-  if (NOT EIGEN_VERSION VERSION_EQUAL CERES_EIGEN_VERSION)
+find_package(Eigen3 ${CERES_EIGEN_VERSION} QUIET)
+if (EIGEN3_FOUND)
+  if (NOT EIGEN3_VERSION_STRING VERSION_EQUAL CERES_EIGEN_VERSION)
     # CMake's VERSION check in FIND_PACKAGE() will accept any version >= the
     # specified version. However, only version = is supported. Improve
     # usability by explaining why we don't accept non-exact version matching.
     ceres_report_not_found("Found Eigen dependency, but the version of Eigen "
-      "found (${EIGEN_VERSION}) does not exactly match the version of Eigen "
+      "found (${EIGEN3_VERSION_STRING}) does not exactly match the version of Eigen "
       "Ceres was compiled with (${CERES_EIGEN_VERSION}). This can cause subtle "
       "bugs by triggering violations of the One Definition Rule. See the "
       "Wikipedia article http://en.wikipedia.org/wiki/One_Definition_Rule "
       "for more details")
   endif ()
   message(STATUS "Found required Ceres dependency: "
-    "Eigen version ${CERES_EIGEN_VERSION} in ${EIGEN_INCLUDE_DIRS}")
-else (EIGEN_FOUND)
+    "Eigen version ${CERES_EIGEN_VERSION} in ${EIGEN3_INCLUDE_DIRS}")
+else (EIGEN3_FOUND)
   ceres_report_not_found("Missing required Ceres "
     "dependency: Eigen version ${CERES_EIGEN_VERSION}, please set "
-    "EIGEN_INCLUDE_DIR.")
-endif (EIGEN_FOUND)
-list(APPEND CERES_INCLUDE_DIRS ${EIGEN_INCLUDE_DIRS})
+    "EIGEN3_INCLUDE_DIR.")
+endif (EIGEN3_FOUND)
+list(APPEND CERES_INCLUDE_DIRS ${EIGEN3_INCLUDE_DIRS})
 
 # Glog.
 include (CMakeFindDependencyMacro)