Replace "cmake -E" with "${CMAKE_COMMAND} -E"

See https://cmake.org/cmake/help/latest/variable/CMAKE_COMMAND.html

Many commands from the block "distcheck" do not work under Windows without MinGW or Cygwin.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 103ba45..7bbcd10 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -93,7 +93,7 @@
 SET(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")
 
 SET(ARCHIVE_NAME ${PACKAGE_NAME}-${PACKAGE_VERSION})
-IF(NOT TARGET dist)
+IF(NOT TARGET dist AND NOT WIN32)
 ADD_CUSTOM_TARGET(dist
   COMMAND git config tar.tar.xz.command "xz -c"
   COMMAND git archive --prefix=${ARCHIVE_NAME}/ -o ${ARCHIVE_NAME}.tar.gz HEAD
@@ -103,11 +103,11 @@
 ADD_CUSTOM_TARGET(distcheck
   COMMAND chmod -R u+w ${ARCHIVE_NAME} ${ARCHIVE_NAME}-build ${ARCHIVE_NAME}-dest 2>/dev/null || true
   COMMAND rm -rf ${ARCHIVE_NAME} ${ARCHIVE_NAME}-build ${ARCHIVE_NAME}-dest
-  COMMAND cmake -E tar xf ${ARCHIVE_NAME}.tar.gz
+  COMMAND ${CMAKE_COMMAND} -E tar xf ${ARCHIVE_NAME}.tar.gz
   COMMAND chmod -R u-w ${ARCHIVE_NAME}
   COMMAND mkdir ${ARCHIVE_NAME}-build
   COMMAND mkdir ${ARCHIVE_NAME}-dest
-  COMMAND cd ${ARCHIVE_NAME}-build && cmake -DCMAKE_INSTALL_PREFIX=../${ARCHIVE_NAME}-dest ../${ARCHIVE_NAME}
+  COMMAND cd ${ARCHIVE_NAME}-build && ${CMAKE_COMMAND} -DCMAKE_INSTALL_PREFIX=../${ARCHIVE_NAME}-dest ../${ARCHIVE_NAME}
   COMMAND cd ${ARCHIVE_NAME}-build && make -j4
   COMMAND cd ${ARCHIVE_NAME}-build && make test
   COMMAND cd ${ARCHIVE_NAME}-build && make install
@@ -120,7 +120,7 @@
   WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
   )
 ADD_DEPENDENCIES(distcheck dist)
-ENDIF(NOT TARGET dist)
+ENDIF(NOT TARGET dist AND NOT WIN32)
 
 IF(BUILD_SHARED_LIBS)
   SET(HAVE_SHARED TRUE)
diff --git a/regress/CMakeLists.txt b/regress/CMakeLists.txt
index 3ccdade..baaae0f 100644
--- a/regress/CMakeLists.txt
+++ b/regress/CMakeLists.txt
@@ -49,8 +49,8 @@
 ADD_CUSTOM_TARGET(testinput
   ALL
   VERBATIM
-  COMMAND cmake -E tar x ${CMAKE_CURRENT_SOURCE_DIR}/manyfiles-zip.zip
-  COMMAND cmake -E tar x ${CMAKE_CURRENT_SOURCE_DIR}/bigzero-zip.zip
+  COMMAND ${CMAKE_COMMAND} -E tar x ${CMAKE_CURRENT_SOURCE_DIR}/manyfiles-zip.zip
+  COMMAND ${CMAKE_COMMAND} -E tar x ${CMAKE_CURRENT_SOURCE_DIR}/bigzero-zip.zip
   DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/manyfiles-zip.zip ${CMAKE_CURRENT_SOURCE_DIR}/bigzero-zip.zip
 )