5 files changed, 47 insertions, 1 deletions
diff --git a/config/header.mk b/config/header.mk
index 55657f8..36ad98e 100644
--- a/config/header.mk
+++ b/config/header.mk
@@ -20,7 +20,11 @@ HEADERS := \
     ${GEN}/posix-spawn-addfchdir.h \
     ${GEN}/posix-spawn-addfchdir-np.h \
     ${GEN}/statx.h \
-    ${GEN}/statx-syscall.h
+    ${GEN}/statx-syscall.h \
+    ${GEN}/strerror-l.h \
+    ${GEN}/strerror-r-gnu.h \
+    ${GEN}/strerror-r-posix.h \
+    ${GEN}/uselocale.h
 
 ${GEN}/config.h: ${HEADERS}
 	${MSG} "[ GEN] ${TGT}"
diff --git a/config/strerror-l.c b/config/strerror-l.c
new file mode 100644
index 0000000..3dcc4d7
--- /dev/null
+++ b/config/strerror-l.c
@@ -0,0 +1,11 @@
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
+
+#include <errno.h>
+#include <locale.h>
+#include <string.h>
+
+int main(void) {
+	locale_t locale = duplocale(LC_GLOBAL_LOCALE);
+	return !strerror_l(ENOMEM, locale);
+}
diff --git a/config/strerror-r-gnu.c b/config/strerror-r-gnu.c
new file mode 100644
index 0000000..26ca0ee
--- /dev/null
+++ b/config/strerror-r-gnu.c
@@ -0,0 +1,11 @@
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
+
+#include <errno.h>
+#include <string.h>
+
+int main(void) {
+	char buf[256];
+	// Check that strerror_r() returns a pointer
+	return *strerror_r(ENOMEM, buf, sizeof(buf));
+}
diff --git a/config/strerror-r-posix.c b/config/strerror-r-posix.c
new file mode 100644
index 0000000..41b2d30
--- /dev/null
+++ b/config/strerror-r-posix.c
@@ -0,0 +1,11 @@
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
+
+#include <errno.h>
+#include <string.h>
+
+int main(void) {
+	char buf[256];
+	// Check that strerror_r() returns an integer
+	return 2 * strerror_r(ENOMEM, buf, sizeof(buf));
+}
diff --git a/config/uselocale.c b/config/uselocale.c
new file mode 100644
index 0000000..a712ff8
--- /dev/null
+++ b/config/uselocale.c
@@ -0,0 +1,9 @@
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
+
+#include <locale.h>
+
+int main(void) {
+	locale_t locale = uselocale((locale_t)0);
+	return locale == LC_GLOBAL_LOCALE;
+}