diff --git a/.Rbuildignore b/.Rbuildignore
index d87a92e..0752ae4 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -1,4 +1,10 @@
 examples
+repo
+revdep
+scripts
+tools
+wiki
+www
 tests/Makefile
 tests/(.+?)\.png$
 tests/(.+?)\.pdf$
@@ -7,6 +13,7 @@ inst/doc/Makefile
 inst/doc/(.+?).md
 inst/doc/(.+?).Rmd
 man/roxygen
+Doxyfile
 LICENSE\.md$
 README\.md$
 CRAN\.md$
@@ -33,6 +40,7 @@ Makefile
 rules.mk
 scripts
 lib
+libs
 library
 check
 www
diff --git a/.github/workflows/r-cmd-check.yml b/.github/workflows/r-cmd-check.yml
index eb080be..7510028 100644
--- a/.github/workflows/r-cmd-check.yml
+++ b/.github/workflows/r-cmd-check.yml
@@ -22,10 +22,8 @@ jobs:
         config:
           - {os: ubuntu-22.04,   r: 'devel', http-user-agent: 'release'}
           - {os: ubuntu-latest,  r: 'release'}
-          - {os: ubuntu-latest,  r: 'oldrel-1'}
           - {os: ubuntu-latest,  r: '4.1.0'}
-          - {os: macOS-11,       r: 'release'}
-          - {os: macOS-12,       r: 'release'}
+          - {os: macOS-latest,   r: 'release'}
           - {os: windows-latest, r: 'release'}
 
     env:
diff --git a/.gitignore b/.gitignore
index 16ab8f2..ec9dce7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,16 +19,15 @@
 *.so
 *.gcda
 *.gcno
-tests/*.pdf
-scripts
+*.pdf
+/scripts
 lib
 library
 check
+repo
+wiki
 www
-*.pdf
-inst/doc/figure
-inst/doc/cache
-hub_cov.R
+tmp
 covr.html
 covr.rds
 .DS_Store
diff --git a/rules.mk b/rules.mk
index 79a6f96..18e5089 100644
--- a/rules.mk
+++ b/rules.mk
@@ -1,4 +1,4 @@
-REXE = R --vanilla
+REXE = $(shell which R) --vanilla
 RSESSION = emacs -f R
 RCMD = $(REXE) CMD
 RCMD_ALT = R --no-save --no-restore CMD
diff --git a/tools/check.env b/tools/check.env
new file mode 100644
index 0000000..a200412
--- /dev/null
+++ b/tools/check.env
@@ -0,0 +1,88 @@
+_R_CHECK_AS_DATA_FRAME_EXPLICIT_METHOD_=true
+_R_CHECK_ALL_NON_ISO_C_=false
+_R_CHECK_ALWAYS_LOG_VIGNETTE_OUTPUT_=false
+_R_CHECK_ASCII_CODE_=true
+_R_CHECK_ASCII_DATA_=true
+_R_CHECK_AUTOCONF_=true
+_R_CHECK_BASHISMS_=true
+_R_CHECK_BOGUS_RETURN_=true
+_R_CHECK_BUILD_VIGNETTES_SEPARATELY_=true
+_R_CHECK_CLEAN_VIGN_TEST_=true
+_R_CHECK_CODE_ASSIGN_TO_GLOBALENV_=true
+_R_CHECK_CODE_ATTACH_=true
+_R_CHECK_CODE_CLASS_IS_STRING_=true
+_R_CHECK_CODE_DATA_INTO_GLOBALENV_=true
+_R_CHECK_CODE_USAGE_VIA_NAMESPACES_=true
+_R_CHECK_CODE_USAGE_WITH_ONLY_BASE_ATTACHED_=true
+_R_CHECK_CODOC_S4_METHODS_=true
+_R_CHECK_COMPACT_DATA_=true
+_R_CHECK_COMPILATION_FLAGS_=true
+_R_CHECK_CONNECTIONS_LEFT_OPEN_=true
+_R_CHECK_CRAN_INCOMING_=false
+_R_CHECK_DATALIST_=true
+_R_CHECK_DEPRECATED_DEFUNCT_=true
+_R_CHECK_DONTTEST_EXAMPLES_=false
+_R_CHECK_DOT_FIRSTLIB_=true
+_R_CHECK_DOT_INTERNAL_=true
+_R_CHECK_EXAMPLE_TIMING_THRESHOLD_=5
+_R_CHECK_EXCESSIVE_IMPORTS_=20
+_R_CHECK_EXECUTABLES_=true
+_R_CHECK_EXECUTABLES_EXCLUSIONS_=false
+_R_CHECK_EXIT_ON_FIRST_ERROR_=false
+_R_CHECK_FF_CALLS_=true
+_R_CHECK_FF_DUP_=true
+_R_CHECK_FORCE_SUGGESTS_=false
+_R_CHECK_FUTURE_FILE_TIMESTAMPS_=true
+_R_CHECK_GCT_N_=0
+_R_CHECK_INSTALL_DEPENDS_=true
+_R_CHECK_LENGTH_1_CONDITION_ =package:_R_CHECK_PACKAGE_NAME_
+_R_CHECK_LENGTH_1_LOGIC2_=package:_R_CHECK_PACKAGE_NAME_,abort,verbose
+_R_CHECK_LICENSE_=true
+_R_CHECK_LIMIT_CORES_=true
+_R_CHECK_MATRIX_DATA_=true
+_R_CHECK_NATIVE_ROUTINE_REGISTRATION_=true
+_R_CHECK_NO_RECOMMENDED_=true
+_R_CHECK_NO_STOP_ON_TEST_ERROR_=true
+_R_CHECK_ORPHANED_=true
+_R_CHECK_OVERWRITE_REGISTERED_S3_METHODS_=true
+_R_CHECK_PACKAGES_USED_IN_TESTS_USE_SUBDIRS_=true
+_R_CHECK_PKG_SIZES_=true
+_R_CHECK_PKG_SIZES_THRESHOLD_=5
+_R_CHECK_PRAGMAS_=true
+_R_CHECK_RD_CHECKRD_MINLEVEL_=-1
+_R_CHECK_RD_CONTENTS_=true
+_R_CHECK_RD_EXAMPLES_T_AND_F_=false
+_R_CHECK_RD_LINE_WIDTHS_=true
+_R_CHECK_RD_STYLE_=true
+_R_CHECK_RD_VALIDATE_RD2HTML_=true
+_R_CHECK_RD_XREFS_=true
+_R_CHECK_REPLACING_IMPORTS_=true
+_R_CHECK_R_DEPENDS_="warn"
+_R_CHECK_R_ON_PATH_=true
+_R_CHECK_S3_METHODS_NOT_REGISTERED_=true
+_R_CHECK_SERIALIZATION_=true
+_R_CHECK_SHLIB_OPENMP_FLAGS_=true
+_R_CHECK_SKIP_ARCH_=none
+_R_CHECK_SRC_MINUS_W_IMPLICIT_=true
+_R_CHECK_SRC_MINUS_W_UNUSED_=true
+_R_CHECK_SUBDIRS_NOCASE_=true
+_R_CHECK_SUBDIRS_STRICT_=default
+_R_CHECK_SUGGESTS_ONLY_=true
+_R_CHECK_SYSTEM_CLOCK_=false
+_R_CHECK_TESTS_NLINES_=13
+_R_CHECK_THINGS_IN_CHECK_DIR_=true
+_R_CHECK_THINGS_IN_OTHER_DIRS_=false
+_R_CHECK_THINGS_IN_TEMP_DIR_=true
+_R_CHECK_TIMINGS_=10
+_R_CHECK_TOPLEVEL_FILES_=true
+_R_CHECK_UNSAFE_CALLS_=true
+_R_CHECK_USE_CODETOOLS_=true
+_R_CHECK_USE_INSTALL_LOG_=true
+_R_CHECK_VC_DIRS_=true
+_R_CHECK_VIGNETTES_NLINES_=10
+_R_CHECK_VIGNETTES_SKIP_RUN_MAYBE_=true
+_R_CHECK_WALL_FORTRAN_=true
+_R_CHECK_XREFS_MIND_SUSPECT_ANCHORS_=false
+_R_CHECK_XREFS_PKGS_ARE_DECLARED_=false
+_R_CHECK_XREFS_USE_ALIASES_FROM_CRAN_=false
+_R_CHECK_CODETOOLS_PROFILE_="suppressLocalUnused=FALSE,suppressPartialMatchArgs=FALSE,suppressParamUnused=TRUE,suppressUndefined=FALSE"