x86-linux-setup.c: Use POSIX basename API

Musl C library only supports POSIX basename function. while glibc has
both GNU extention as well as POSIX basename implemented. Switch to
using posix version, so it can work across musl and glibc

basename prototype has been removed from string.h from latest musl [1]
compilers e.g. clang-18/GCC-14 flags the absense of prototype as error.
therefore include libgen.h for providing it.

[1] https://git.musl-libc.org/cgit/musl/commit/?id=725e17ed6dff4d0cd22487bb64470881e86a92e7

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Simon Horman <horms@kernel.org>

kexec/arch/i386/x86-linux-setup.c

@@ -14,6 +14,7 @@
  *
  */
 #define _GNU_SOURCE
+#include <libgen.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
@@ -329,12 +330,14 @@ static int add_edd_entry(struct x86_linux_param_header *real_mode,
 	memset(edd_info, 0, sizeof(struct edd_info));
 
 	/* extract the device number */
-	if (sscanf(basename(sysfs_name), "int13_dev%hhx", &devnum) != 1) {
+	char* sysfs_name_copy = strdup(sysfs_name);
+	if (sscanf(basename(sysfs_name_copy), "int13_dev%hhx", &devnum) != 1) {
 		fprintf(stderr, "Invalid format of int13_dev dir "
-				"entry: %s\n", basename(sysfs_name));
+				"entry: %s\n", basename(sysfs_name_copy));
+		free(sysfs_name_copy);
 		return -1;
 	}
-
+	free(sysfs_name_copy);
 	/* if there's a MBR signature, then add it */
 	if (file_scanf(sysfs_name, "mbr_signature", "0x%x", &mbr_sig) == 1) {
 		real_mode->edd_mbr_sig_buffer[*current_mbr] = mbr_sig;