STYLE: Remove CMake-language block-end command arguments

Ancient versions of CMake required else(), endif(), and similar block
termination commands to have arguments matching the command starting the block.
This is no longer the preferred style.

CMakeLists.txt

@@ -54,13 +54,13 @@ endif()
 if(EIGEN_BRANCH_OUTPUT MATCHES "default")
 string(REGEX MATCH "^changeset: *[0-9]*:([0-9;a-f]+).*" EIGEN_HG_CHANGESET_MATCH "${EIGEN_HGTIP_OUTPUT}")
 set(EIGEN_HG_CHANGESET "${CMAKE_MATCH_1}")
-endif(EIGEN_BRANCH_OUTPUT MATCHES "default")
+endif()
 #...and show it next to the version number
 if(EIGEN_HG_CHANGESET)
   set(EIGEN_VERSION "${EIGEN_VERSION_NUMBER} (mercurial changeset ${EIGEN_HG_CHANGESET})")
-else(EIGEN_HG_CHANGESET)
+else()
   set(EIGEN_VERSION "${EIGEN_VERSION_NUMBER}")
-endif(EIGEN_HG_CHANGESET)
+endif()
 
 
 include(CheckCXXCompilerFlag)
@@ -79,7 +79,7 @@ macro(ei_add_cxx_compiler_flag FLAG)
   if(COMPILER_SUPPORT_${SFLAG})
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${FLAG}")
   endif()
-endmacro(ei_add_cxx_compiler_flag)
+endmacro()
 
 check_cxx_compiler_flag("-std=c++11" EIGEN_COMPILER_SUPPORT_CPP11)
 
@@ -319,7 +319,7 @@ if(NOT MSVC)
     endif()
   endif()
 
-else(NOT MSVC)
+else()
 
   # C4127 - conditional expression is constant
   # C4714 - marked as __forceinline not inlined (I failed to deactivate it selectively)
@@ -347,9 +347,9 @@ else(NOT MSVC)
     if(NOT CMAKE_CL_64)
       # arch is not supported on 64 bit systems, SSE is enabled automatically.
       set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /arch:SSE2")
-    endif(NOT CMAKE_CL_64)
+    endif()
     message(STATUS "Enabling SSE2 in tests/examples")
-  endif(EIGEN_TEST_SSE2)
+  endif()
 
   option(EIGEN_TEST_AVX "Enable/Disable AVX in tests/examples" OFF)
   if(EIGEN_TEST_AVX)
@@ -363,7 +363,7 @@ else(NOT MSVC)
     message(STATUS "Enabling FMA/AVX2 in tests/examples")
   endif()
 
-endif(NOT MSVC)
+endif()
 
 option(EIGEN_TEST_NO_EXPLICIT_VECTORIZATION "Disable explicit vectorization in tests/examples" OFF)
 option(EIGEN_TEST_X87 "Force using X87 instructions. Implies no vectorization." OFF)
@@ -440,9 +440,9 @@ macro(ei_add_target_property target prop value)
   # if the property wasn't previously set, ${previous} is now "previous-NOTFOUND" which cmake allows catching with plain if()
   if(NOT previous)
     set(previous "")
-  endif(NOT previous)
+  endif()
   set_target_properties(${target} PROPERTIES ${prop} "${previous} ${value}")
-endmacro(ei_add_target_property)
+endmacro()
 
 install(FILES
   signature_of_eigen3_matrix_library
@@ -489,11 +489,11 @@ if(EIGEN_TEST_SYCL)
   if(EIGEN_SYCL_TRISYCL)
     message(STATUS "Using triSYCL")
     include(FindTriSYCL)
-  else(EIGEN_SYCL_TRISYCL)
+  else()
     message(STATUS "Using ComputeCPP SYCL")
     include(FindComputeCpp)
-  endif(EIGEN_SYCL_TRISYCL)
-endif(EIGEN_TEST_SYCL)
+  endif()
+endif()
 
 add_subdirectory(unsupported)
 
@@ -505,11 +505,11 @@ add_subdirectory(scripts EXCLUDE_FROM_ALL)
 # TODO: consider also replacing EIGEN_BUILD_BTL by a custom target "make btl"?
 if(EIGEN_BUILD_BTL)
   add_subdirectory(bench/btl EXCLUDE_FROM_ALL)
-endif(EIGEN_BUILD_BTL)
+endif()
 
 if(NOT WIN32)
   add_subdirectory(bench/spbench EXCLUDE_FROM_ALL)
-endif(NOT WIN32)
+endif()
 
 configure_file(scripts/cdashtesting.cmake.in cdashtesting.cmake @ONLY)
 
@@ -605,7 +605,7 @@ if (NOT CMAKE_VERSION VERSION_LESS 3.0)
 
   install (EXPORT Eigen3Targets NAMESPACE Eigen3:: DESTINATION ${CMAKEPACKAGE_INSTALL_DIR})
 
-else (NOT CMAKE_VERSION VERSION_LESS 3.0)
+else ()
   # Fallback to legacy Eigen3Config.cmake without the imported target
 
   # If CMakePackageConfigHelpers module is available (CMake >= 2.8.8)
@@ -635,7 +635,7 @@ else (NOT CMAKE_VERSION VERSION_LESS 3.0)
                                     VERSION ${EIGEN_VERSION_NUMBER}
                                     COMPATIBILITY SameMajorVersion )
 
-endif (NOT CMAKE_VERSION VERSION_LESS 3.0)
+endif ()
 
 install ( FILES ${CMAKE_CURRENT_SOURCE_DIR}/cmake/UseEigen3.cmake
                 ${CMAKE_CURRENT_BINARY_DIR}/Eigen3Config.cmake