diff --git a/Makefile.in b/Makefile.in
index c4055c3be..2e958c259 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -71,7 +71,6 @@ LIBTOOL_DEPS = @LIBTOOL_DEPS@
 SHELL = @SHELL@
 
 EGREP = @EGREP@
-GREP = @GREP@
 SED = @SED@
 
 INSTALL = $(SHELL) $(scriptdir)/install-sh -c
@@ -119,7 +118,7 @@ check check-verbose check-fuzzer fuzz pre-install: config.status
 	done
 
 uncrustify.files: Makefile
-	$(GREP) '\.[ch]$$' $(top_srcdir)/MANIFEST | $(EGREP) -v '(/zlib/|/(arc4random|arc4random_uniform|chacha_private|charclass|fnmatch|getaddrinfo|getcwd|getdate|getentropy|getopt|getopt_long|glob|gram|inet_ntop|inet_pton|log_server.pb-c|mktemp|pw_dup|reallocarray|mktemp_test|protobuf-c|snprintf|stdbool|strlcat|strlcpy|sudo_queue|toke)\.[ch]$$)'  > uncrustify.files
+	$(EGREP) '\.[ch]$$' $(top_srcdir)/MANIFEST | $(EGREP) -v '(/zlib/|/(arc4random|arc4random_uniform|chacha_private|charclass|fnmatch|getaddrinfo|getcwd|getdate|getentropy|getopt|getopt_long|glob|gram|inet_ntop|inet_pton|log_server.pb-c|mktemp|pw_dup|reallocarray|mktemp_test|protobuf-c|snprintf|stdbool|strlcat|strlcpy|sudo_queue|toke)\.[ch]$$)'  > uncrustify.files
 
 reformat: uncrustify.files
 	( cd $(top_srcdir) && uncrustify -c etc/uncrustify.cfg --replace --no-backup -F $(top_builddir)/uncrustify.files )
diff --git a/lib/eventlog/Makefile.in b/lib/eventlog/Makefile.in
index 45b9ad2e9..0796154ad 100644
--- a/lib/eventlog/Makefile.in
+++ b/lib/eventlog/Makefile.in
@@ -33,7 +33,7 @@ incdir = $(top_srcdir)/include
 # Compiler & tools to use
 CC = @CC@
 LIBTOOL = @LIBTOOL@
-GREP = @GREP@
+EGREP = @EGREP@
 
 # C preprocessor flags
 CPPFLAGS = -I$(incdir) -I$(top_builddir) -I$(srcdir) -I$(top_srcdir) @CPPFLAGS@
@@ -152,11 +152,9 @@ check-fuzzer:
 
 check: $(TEST_PROGS) check-fuzzer
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
diff --git a/lib/iolog/Makefile.in b/lib/iolog/Makefile.in
index 2dde029d0..6f35db0e4 100644
--- a/lib/iolog/Makefile.in
+++ b/lib/iolog/Makefile.in
@@ -35,7 +35,7 @@ cross_compiling = @CROSS_COMPILING@
 CC = @CC@
 LIBTOOL = @LIBTOOL@
 SHA1SUM = @SHA1SUM@
-GREP = @GREP@
+EGREP = @EGREP@
 SED = @SED@
 
 # Libraries
@@ -200,11 +200,9 @@ fuzz_iolog_json_seed_corpus.zip:
 	rm -rf $$tdir
 
 run-fuzz_iolog_json: fuzz_iolog_json
-	if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-	    LC_ALL=C.UTF-8; export LC_ALL; \
-	else \
-	    LC_ALL=C; export LC_ALL; \
-	fi; \
+	l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	test -n "$$l" || l="C"; \
+	LC_ALL="$$l"; export LC_ALL; \
 	unset LANG || LANG=; \
 	unset LANGUAGE || LANGUAGE=; \
 	MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -227,11 +225,9 @@ fuzz_iolog_legacy_seed_corpus.zip:
 	rm -rf $$tdir
 
 run-fuzz_iolog_legacy: fuzz_iolog_legacy
-	if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-	    LC_ALL=C.UTF-8; export LC_ALL; \
-	else \
-	    LC_ALL=C; export LC_ALL; \
-	fi; \
+	l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	test -n "$$l" || l="C"; \
+	LC_ALL="$$l"; export LC_ALL; \
 	unset LANG || LANG=; \
 	unset LANGUAGE || LANGUAGE=; \
 	MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -254,11 +250,9 @@ fuzz_iolog_timing_seed_corpus.zip:
 	rm -rf $$tdir
 
 run-fuzz_iolog_timing: fuzz_iolog_timing
-	if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-	    LC_ALL=C.UTF-8; export LC_ALL; \
-	else \
-	    LC_ALL=C; export LC_ALL; \
-	fi; \
+	l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	test -n "$$l" || l="C"; \
+	LC_ALL="$$l"; export LC_ALL; \
 	unset LANG || LANG=; \
 	unset LANGUAGE || LANGUAGE=; \
 	MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -308,11 +302,9 @@ fuzz: run-fuzz_iolog_json run-fuzz_iolog_legacy run-fuzz_iolog_timing
 
 check-fuzzer: $(FUZZ_PROGS)
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -327,11 +319,9 @@ check-fuzzer: $(FUZZ_PROGS)
 
 check: $(TEST_PROGS) check-fuzzer
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
diff --git a/lib/util/Makefile.in b/lib/util/Makefile.in
index ad97748f8..8d52252c8 100644
--- a/lib/util/Makefile.in
+++ b/lib/util/Makefile.in
@@ -55,7 +55,7 @@ CPP = @CPP@
 HOSTCPP = @CPP_FOR_BUILD@
 LIBTOOL = @LIBTOOL@
 SHA1SUM = @SHA1SUM@
-GREP = @GREP@
+EGREP = @EGREP@
 SED = @SED@
 AWK = @AWK@
 
@@ -342,11 +342,9 @@ fuzz_sudo_conf_seed_corpus.zip:
 	rm -rf $$tdir
 
 run-fuzz_sudo_conf: fuzz_sudo_conf
-	if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-	    LC_ALL=C.UTF-8; export LC_ALL; \
-	else \
-	    LC_ALL=C; export LC_ALL; \
-	fi; \
+	l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	test -n "$$l" || l="C"; \
+	LC_ALL="$$l"; export LC_ALL; \
 	unset LANG || LANG=; \
 	unset LANGUAGE || LANGUAGE=; \
 	MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -408,11 +406,9 @@ fuzz: run-fuzz_sudo_conf
 
 check-fuzzer: $(FUZZ_PROGS)
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -424,11 +420,9 @@ check-fuzzer: $(FUZZ_PROGS)
 # Note: some regress checks are run from srcdir for consistent error messages
 check: $(TEST_PROGS) check-fuzzer
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -449,9 +443,9 @@ check: $(TEST_PROGS) check-fuzzer
 	    if test -f globtest; then \
 		mkdir -p `$(SED) 's@/[^/]*$$@@' $(srcdir)/regress/glob/files | sort -u`; \
 		touch `cat $(srcdir)/regress/glob/files`; \
-		chmod 0755 `$(GREP) '/r[^/]*$$' $(srcdir)/regress/glob/files`; \
-		chmod 0444 `$(GREP) '/s[^/]*$$' $(srcdir)/regress/glob/files`; \
-		chmod 0711 `$(GREP) '/t[^/]*$$' $(srcdir)/regress/glob/files`; \
+		chmod 0755 `$(EGREP) '/r[^/]*$$' $(srcdir)/regress/glob/files`; \
+		chmod 0444 `$(EGREP) '/s[^/]*$$' $(srcdir)/regress/glob/files`; \
+		chmod 0711 `$(EGREP) '/t[^/]*$$' $(srcdir)/regress/glob/files`; \
 		./globtest $(srcdir)/regress/glob/globtest.in || rval=`expr $$rval + $$?`; \
 		rm -rf fake; \
 	    fi; \
diff --git a/logsrvd/Makefile.in b/logsrvd/Makefile.in
index c9ba8658c..c7f2e2d88 100644
--- a/logsrvd/Makefile.in
+++ b/logsrvd/Makefile.in
@@ -36,7 +36,7 @@ cross_compiling = @CROSS_COMPILING@
 CC = @CC@
 LIBTOOL = @LIBTOOL@
 SHA1SUM = @SHA1SUM@
-GREP = @GREP@
+EGREP = @EGREP@
 SED = @SED@
 
 # Our install program supports extra flags...
@@ -195,11 +195,9 @@ fuzz_logsrvd_conf_seed_corpus.zip:
 	rm -rf $$tdir
 
 run-fuzz_logsrvd_conf: fuzz_logsrvd_conf
-	if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-	    LC_ALL=C.UTF-8; export LC_ALL; \
-	else \
-	    LC_ALL=C; export LC_ALL; \
-	fi; \
+	l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	test -n "$$l" || l="C"; \
+	LC_ALL="$$l"; export LC_ALL; \
 	unset LANG || LANG=; \
 	unset LANGUAGE || LANGUAGE=; \
 	MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -258,11 +256,9 @@ fuzz: run-fuzz_logsrvd_conf
 
 check-fuzzer: $(FUZZ_PROGS)
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -273,11 +269,9 @@ check-fuzzer: $(FUZZ_PROGS)
 
 check: $(TEST_PROGS) check-fuzzer
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
diff --git a/plugins/python/Makefile.in b/plugins/python/Makefile.in
index 1510d22e7..ad83e1ab3 100644
--- a/plugins/python/Makefile.in
+++ b/plugins/python/Makefile.in
@@ -36,7 +36,7 @@ cross_compiling = @CROSS_COMPILING@
 # Compiler & tools to use
 CC = @CC@
 LIBTOOL = @LIBTOOL@
-GREP = @GREP@
+EGREP = @EGREP@
 SED = @SED@
 AWK = @AWK@
 
@@ -228,11 +228,9 @@ check-fuzzer:
 
 check: $(TEST_PROGS) check-fuzzer
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
diff --git a/plugins/sudoers/Makefile.in b/plugins/sudoers/Makefile.in
index e24a85520..5c6beeb8e 100644
--- a/plugins/sudoers/Makefile.in
+++ b/plugins/sudoers/Makefile.in
@@ -47,7 +47,7 @@ LIBTOOL = @LIBTOOL@
 SHA1SUM = @SHA1SUM@
 FLEX = @FLEX@
 YACC = @YACC@
-GREP = @GREP@
+EGREP = @EGREP@
 SED = @SED@
 AWK = @AWK@
 
@@ -431,11 +431,9 @@ fuzz_policy_seed_corpus.zip:
 	rm -rf $$tdir
 
 run-fuzz_policy: fuzz_policy
-	if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-	    LC_ALL=C.UTF-8; export LC_ALL; \
-	else \
-	    LC_ALL=C; export LC_ALL; \
-	fi; \
+	l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	test -n "$$l" || l="C"; \
+	LC_ALL="$$l"; export LC_ALL; \
 	unset LANG || LANG=; \
 	unset LANGUAGE || LANGUAGE=; \
 	MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -458,11 +456,9 @@ fuzz_sudoers_seed_corpus.zip:
 	rm -rf $$tdir
 
 run-fuzz_sudoers: fuzz_sudoers
-	if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-	    LC_ALL=C.UTF-8; export LC_ALL; \
-	else \
-	    LC_ALL=C; export LC_ALL; \
-	fi; \
+	l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	test -n "$$l" || l="C"; \
+	LC_ALL="$$l"; export LC_ALL; \
 	unset LANG || LANG=; \
 	unset LANGUAGE || LANGUAGE=; \
 	MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -485,11 +481,9 @@ fuzz_sudoers_ldif_seed_corpus.zip:
 	rm -rf $$tdir
 
 run-fuzz_sudoers_ldif: fuzz_sudoers_ldif
-	if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-	    LC_ALL=C.UTF-8; export LC_ALL; \
-	else \
-	    LC_ALL=C; export LC_ALL; \
-	fi; \
+	l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	test -n "$$l" || l="C"; \
+	LC_ALL="$$l"; export LC_ALL; \
 	unset LANG || LANG=; \
 	unset LANGUAGE || LANGUAGE=; \
 	MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -635,11 +629,9 @@ fuzz: run-fuzz_policy run-fuzz_sudoers run-fuzz_sudoers_ldif
 
 check-fuzzer: $(FUZZ_PROGS)
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
@@ -654,11 +646,9 @@ check-fuzzer: $(FUZZ_PROGS)
 
 check: $(TEST_PROGS) visudo testsudoers cvtsudoers check-fuzzer
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \
diff --git a/src/Makefile.in b/src/Makefile.in
index bfa941565..850b73212 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -35,7 +35,7 @@ cross_compiling = @CROSS_COMPILING@
 # Compiler & tools to use
 CC = @CC@
 LIBTOOL = @LIBTOOL@
-GREP = @GREP@
+EGREP = @EGREP@
 SED = @SED@
 AWK = @AWK@
 
@@ -332,11 +332,9 @@ check-fuzzer:
 
 check: $(TEST_PROGS) check-fuzzer
 	@if test X"$(cross_compiling)" != X"yes"; then \
-	    if locale -a 2>&1 | $(GREP) '^C.UTF-8$$' >/dev/null 2>&1; then \
-		LC_ALL=C.UTF-8; export LC_ALL; \
-	    else \
-		LC_ALL=C; export LC_ALL; \
-	    fi; \
+	    l=`locale -a 2>&1 | $(EGREP) -i '^C.UTF-?8$$'`; \
+	    test -n "$$l" || l="C"; \
+	    LC_ALL="$$l"; export LC_ALL; \
 	    unset LANG || LANG=; \
 	    unset LANGUAGE || LANGUAGE=; \
 	    MALLOC_OPTIONS=S; export MALLOC_OPTIONS; \