compat: add canonicalize_file_name

the POSIX 2008 behaviour of realpath is not available everywhere so we
provide a simple wrapper function.  We use (and provide) the gnu
extension canonicalize_file_name to make it cleaner to test for the
feature we need; otherwise we have to rely on realpath segfaulting if
the second argument is null.

1 files changed, 10 insertions, 0 deletions

diff --git a/compat/have_canonicalize_file_name.c b/compat/have_canonicalize_file_name.c
new file mode 100644
index 00000000..24c848ec
--- /dev/null
+++ b/compat/have_canonicalize_file_name.c
@@ -0,0 +1,10 @@
+#define _GNU_SOURCE
+#include <stdlib.h>
+
+int main()
+{
+    char *found;
+    char *string;
+
+    found = canonicalize_file_name (string);
+}