musl defines id_t as unsigned but doesn't use the _ID_T to detect its
definition. This causes the type to be redefined as an int by fakeroot
which causes a compilation error.

diff -upr fakeroot-1.27.orig/libfakeroot.c fakeroot-1.27/libfakeroot.c
--- fakeroot-1.27.orig/libfakeroot.c	2022-01-30 11:30:25.198506844 +0100
+++ fakeroot-1.27/libfakeroot.c	2022-01-30 11:30:41.928524429 +0100
@@ -133,13 +133,6 @@
 #define INT_SEND_STAT(a,b) SEND_STAT(a,b,_STAT_VER)
 #define INT_SEND_GET_XATTR(a,b) SEND_GET_XATTR(a,b,_STAT_VER)
 #define INT_SEND_GET_STAT(a,b) SEND_GET_STAT(a,b)
-
-/* 10.10 uses id_t in getpriority/setpriority calls, so pretend
-   id_t is used everywhere, just happens to be int on some OSes */
-#ifndef _ID_T
-#define _ID_T
-typedef int id_t;
-#endif
 #endif
 
 #include <sys/types.h>