diff --git a/configure b/configure
index 90c1540bc767ecda5b25a2500d39a73b353fb859..37ac28bac29fb0424575723a65129142be115658 100755
--- a/configure
+++ b/configure
@@ -18690,7 +18690,7 @@ LDFLAGS="${saved_sanitize_LDFLAGS}"
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -Wdeclaration-after-statement support" >&5
 $as_echo_n "checking for -Wdeclaration-after-statement support... " >&6; }
-if $(${CC} -Wdeclaration-after-statement -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
+if $(${CC} -Wdeclaration-after-statement -Werror -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
 	AST_DECLARATION_AFTER_STATEMENT=-Wdeclaration-after-statement
@@ -18742,7 +18742,7 @@ fi
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -Wno-format-truncation" >&5
 $as_echo_n "checking for -Wno-format-truncation... " >&6; }
-if $(${CC} -O2 -Wno-format-truncation -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
+if $(${CC} -Wno-format-truncation -Werror -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
 	AST_NO_FORMAT_TRUNCATION=-Wno-format-truncation
@@ -18755,7 +18755,7 @@ fi
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for -Wshadow" >&5
 $as_echo_n "checking for -Wshadow... " >&6; }
-if $(${CC} -Wshadow -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
+if $(${CC} -Wshadow -Werror -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
 	AST_SHADOW_WARNINGS=-Wshadow
diff --git a/configure.ac b/configure.ac
index 0a4fb478987ab6c767133028bc024a25126b3663..f0a978ee4bf52dc8b634973affd7f5f0b9c2b47f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1224,7 +1224,7 @@ LDFLAGS="${saved_sanitize_LDFLAGS}"
 AC_SUBST(AST_UNDEFINED_SANITIZER)
 
 AC_MSG_CHECKING(for -Wdeclaration-after-statement support)
-if $(${CC} -Wdeclaration-after-statement -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
+if $(${CC} -Wdeclaration-after-statement -Werror -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
 	AC_MSG_RESULT(yes)
 	AST_DECLARATION_AFTER_STATEMENT=-Wdeclaration-after-statement
 else
@@ -1264,7 +1264,7 @@ fi
 AC_SUBST(AST_NO_STRICT_OVERFLOW)
 
 AC_MSG_CHECKING(for -Wno-format-truncation)
-if $(${CC} -O2 -Wno-format-truncation -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
+if $(${CC} -Wno-format-truncation -Werror -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
 	AC_MSG_RESULT(yes)
 	AST_NO_FORMAT_TRUNCATION=-Wno-format-truncation
 else
@@ -1274,7 +1274,7 @@ fi
 AC_SUBST(AST_NO_FORMAT_TRUNCATION)
 
 AC_MSG_CHECKING(for -Wshadow)
-if $(${CC} -Wshadow -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
+if $(${CC} -Wshadow -Werror -S -o /dev/null -xc /dev/null > /dev/null 2>&1); then
 	AC_MSG_RESULT(yes)
 	AST_SHADOW_WARNINGS=-Wshadow
 else