diff --git a/Makefile b/Makefile
index c84f266ce7..430a0942eb 100644
--- a/Makefile
+++ b/Makefile
@@ -546,7 +546,8 @@ libof-check-installed-headers-c := testsuite
 $(objpfx)check-installed-headers-c.out: \
     scripts/check-installed-headers.sh $(headers)
 	$(SHELL) $(..)scripts/check-installed-headers.sh c $(supported-fortify) \
-	  "$(CC) $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
+	  "$(CC) $(test-config-cflags-finput-charset-ascii) \
+	     $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
 
@@ -556,7 +557,8 @@ libof-check-installed-headers-cxx := testsuite
 $(objpfx)check-installed-headers-cxx.out: \
     scripts/check-installed-headers.sh $(headers)
 	$(SHELL) $(..)scripts/check-installed-headers.sh c++ $(supported-fortify) \
-	  "$(CXX) $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
+	  "$(CXX) $(test-config-cxxflags-finput-charset-ascii) \
+	     $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
 endif # $(CXX)
diff --git a/Rules b/Rules
index 713c225d2e..cd98fcb006 100644
--- a/Rules
+++ b/Rules
@@ -86,7 +86,8 @@ libof-check-installed-headers-c := testsuite
 $(objpfx)check-installed-headers-c.out: \
     $(..)scripts/check-installed-headers.sh $(headers)
 	$(SHELL) $(..)scripts/check-installed-headers.sh c $(supported-fortify) \
-	  "$(CC) $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
+	  "$(CC) $(test-config-cflags-finput-charset-ascii) \
+	     $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
 
@@ -98,7 +99,8 @@ libof-check-installed-headers-cxx := testsuite
 $(objpfx)check-installed-headers-cxx.out: \
     $(..)scripts/check-installed-headers.sh $(headers)
 	$(SHELL) $(..)scripts/check-installed-headers.sh c++ $(supported-fortify) \
-	  "$(CXX) $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
+	  "$(CXX) $(test-config-cxxflags-finput-charset-ascii) \
+	     $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
 endif # $(CXX)
diff --git a/aclocal.m4 b/aclocal.m4
index fb4c1ef1c4..e06366cdb2 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -167,6 +167,12 @@ AC_DEFUN([LIBC_TRY_CC_OPTION],
 [AS_IF([AC_TRY_COMMAND([${CC-cc} $1 -xc /dev/null -S -o /dev/null])],
 	[$2], [$3])])
 
+dnl Test a C++ compiler option or options with an empty input file.
+dnl LIBC_TRY_CXX_OPTION([options], [action-if-true], [action-if-false])
+AC_DEFUN([LIBC_TRY_CXX_OPTION],
+[AS_IF([AC_TRY_COMMAND([${CXX-c++} $1 -xc++ /dev/null -S -o /dev/null])],
+	[$2], [$3])])
+
 dnl Find and source sysdeps/*/preconfigure.
 dnl LIBC_PRECONFIGURE([$srcdir], [for])
 AC_DEFUN([LIBC_PRECONFIGURE], [dnl
@@ -447,3 +453,26 @@ LIBC_CHECK_TEST_CXX(
     fi])
 )
 rm -f conftest*])
+
+dnl Test a TEST_CC compiler option or options with an empty input file.
+dnl LIBC_TRY_TEST_CC_OPTION([message], [options],
+dnl   [TEST_CC-cache-id], [TEST_CC-action-if-true], [TEST_CC-action-if-false])
+AC_DEFUN([LIBC_TRY_TEST_CC_OPTION],
+[
+LIBC_CHECK_TEST_CC(
+  AC_CACHE_CHECK([$1 in testing], $3,
+    [LIBC_TRY_CC_OPTION([$2], [$4], [$5])])
+  )
+])
+
+dnl Test a TEST_CXX compiler option or options with an empty input file.
+dnl LIBC_TRY_TEST_CXX_OPTION([message], [options],
+dnl   [TEST_CXX-cache-id], [TEST_CXX-action-if-true],
+dnl   [TEST_CXX-action-if-false])
+AC_DEFUN([LIBC_TRY_TEST_CXX_OPTION],
+[
+LIBC_CHECK_TEST_CXX(
+  AC_CACHE_CHECK([$1 in testing], $3,
+    [LIBC_TRY_CXX_OPTION([$2], [$4], [$5])])
+  )
+])
diff --git a/configure b/configure
index e9c18316fe..b899d39717 100755
--- a/configure
+++ b/configure
@@ -7774,6 +7774,74 @@ config_vars="$config_vars
 cc-option-wimplicit-fallthrough = $libc_cv_cc_wimplicit_fallthrough"
 
 
+
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking -finput-charset=ascii in testing" >&5
+printf %s "checking -finput-charset=ascii in testing... " >&6; }
+if test ${libc_cv_test_cflags_finput_charset_ascii+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if { ac_try='${CC-cc} -c -Werror -finput-charset=ascii -xc /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_test_cflags_finput_charset_ascii="-finput-charset=ascii"
+else case e in #(
+  e) libc_cv_test_cflags_finput_charset_ascii=
+ ;;
+esac
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_cflags_finput_charset_ascii" >&5
+printf "%s\n" "$libc_cv_test_cflags_finput_charset_ascii" >&6; }
+
+CC="$saved_CC"
+
+
+config_vars="$config_vars
+test-config-cflags-finput-charset-ascii = $libc_cv_test_cflags_finput_charset_ascii"
+
+
+
+saved_CXX="$CXX"
+CXX="$TEST_CXX"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking -finput-charset=ascii in testing" >&5
+printf %s "checking -finput-charset=ascii in testing... " >&6; }
+if test ${libc_cv_test_cxxflags_finput_charset_ascii+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if { ac_try='${CXX-c++} -c -Werror -finput-charset=ascii -xc++ /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_test_cxxflags_finput_charset_ascii="-finput-charset=ascii"
+else case e in #(
+  e) libc_cv_test_cxxflags_finput_charset_ascii=
+ ;;
+esac
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_cxxflags_finput_charset_ascii" >&5
+printf "%s\n" "$libc_cv_test_cxxflags_finput_charset_ascii" >&6; }
+
+CXX="$saved_CXX"
+
+
+config_vars="$config_vars
+test-config-cxxflags-finput-charset-ascii = $libc_cv_test_cxxflags_finput_charset_ascii"
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libgd" >&5
 printf %s "checking for libgd... " >&6; }
 if test "$with_gd" != "no"; then
diff --git a/configure.ac b/configure.ac
index 85c92e5083..6eaf83b8dc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1527,6 +1527,26 @@ LIBC_CONFIG_VAR([cc-option-wimplicit-fallthrough],
 		[$libc_cv_cc_wimplicit_fallthrough])
 AC_SUBST(libc_cv_test_cc_wimplicit_fallthrough)
 
+dnl Check if TEST_CC supports -finput-charset=ascii.
+LIBC_TRY_TEST_CC_OPTION([-finput-charset=ascii],
+  [-c -Werror -finput-charset=ascii],
+  libc_cv_test_cflags_finput_charset_ascii,
+  [libc_cv_test_cflags_finput_charset_ascii="-finput-charset=ascii"],
+  [libc_cv_test_cflags_finput_charset_ascii=]
+)
+LIBC_CONFIG_VAR(test-config-cflags-finput-charset-ascii,
+		$libc_cv_test_cflags_finput_charset_ascii)
+
+dnl Check if TEST_CXX supports -finput-charset=ascii.
+LIBC_TRY_TEST_CXX_OPTION([-finput-charset=ascii],
+  [-c -Werror -finput-charset=ascii],
+  libc_cv_test_cxxflags_finput_charset_ascii,
+  [libc_cv_test_cxxflags_finput_charset_ascii="-finput-charset=ascii"],
+  [libc_cv_test_cxxflags_finput_charset_ascii=]
+)
+LIBC_CONFIG_VAR(test-config-cxxflags-finput-charset-ascii,
+		$libc_cv_test_cxxflags_finput_charset_ascii)
+
 dnl Check whether we have the gd library available.
 AC_MSG_CHECKING(for libgd)
 if test "$with_gd" != "no"; then
diff --git a/scripts/check-installed-headers.sh b/scripts/check-installed-headers.sh
index b8cdcbf858..64cbfda544 100644
--- a/scripts/check-installed-headers.sh
+++ b/scripts/check-installed-headers.sh
@@ -130,8 +130,7 @@ $expanded_lib_mode
 #include <$header>
 int avoid_empty_translation_unit;
 EOF
-                if $cc_cmd -finput-charset=ascii -fsyntax-only $lang_mode \
-		           "$cih_test_c" 2>&1
+                if $cc_cmd -fsyntax-only $lang_mode "$cih_test_c" 2>&1
                 then :
                 else failed=1
                 fi