build: fix musl build errors

libgen.h must be included to silence a compiler error regarding the
basename() function missing when building with musl libc.

The basename() function call in libnvme/src/nvme/linux.c:__nvme_transport_handle_open_direct()
causes a (fatal) compilation warning due to GNU using this declaration of basename:
char *basename (const char *filename)
and POSIX (and also musl) ommiting const. It is thus possible that the const char *devname
would be modified by basename().

The solution to the problem above is to use the internal implementation of basename from glibc
directly and avoid these API compatibility problems.

Signed-off-by: Michal Rábek <[email protected]>

Author: MichaelRabek

libnvme/src/nvme/linux.c

@@ -12,6 +12,10 @@
 #include <string.h>
 #include <errno.h>
 
+#ifndef _GNU_SOURCE
+#include <libgen.h>
+#endif
+
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -83,7 +87,11 @@ static int __nvme_transport_handle_open_direct(struct nvme_transport_handle *hdl
 {
 	struct nvme_passthru_cmd dummy = { 0 };
 	_cleanup_free_ char *path = NULL;
-	char *name = basename(devname);
+	/* This used instead of basename() due to behavioral differences between
+	 * the POSIX and the GNU version. These two lines are the glibc implementation.
+	 * Original source: https://github.com/bminor/glibc/blob/master/string/basename.c */
+	const char *name = strrchr(devname, '/');
+	name = name ? name + 1 : devname;
 	int ret, id, ns;
 	bool c = true;