Fix building squashfs-tools against musl

Include sys/sysmacros.h for makedev to fix building squashfs-tools
against musl libc.

Bug: 190084016
Test: m USE_HOST_MUSL=true host-native
Change-Id: Id915eeacf9e31eb3e5c973ad11427b91d8ebb9dd
diff --git a/squashfs-tools/mksquashfs.c b/squashfs-tools/mksquashfs.c
index dd75aaa..f122c25 100644
--- a/squashfs-tools/mksquashfs.c
+++ b/squashfs-tools/mksquashfs.c
@@ -50,6 +50,7 @@
 #include <sys/wait.h>
 #include <limits.h>
 #include <ctype.h>
+#include <sys/sysmacros.h>
 
 #ifndef FNM_EXTMATCH /* glibc extension */
     #define FNM_EXTMATCH 0
diff --git a/squashfs-tools/unsquashfs.c b/squashfs-tools/unsquashfs.c
index 0dbc4c2..643883b 100644
--- a/squashfs-tools/unsquashfs.c
+++ b/squashfs-tools/unsquashfs.c
@@ -37,6 +37,7 @@
 #include <sys/sysinfo.h>
 #endif
 
+#include <sys/sysmacros.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/resource.h>