sgidef.h does not exist on musl and its not needed to compile

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Upstream-Status: Pending
Index: git/src/base/linux_syscall_support.h
===================================================================
--- git.orig/src/base/linux_syscall_support.h
+++ git/src/base/linux_syscall_support.h
@@ -164,7 +164,7 @@ extern "C" {
 #include <endian.h>
 #include <fcntl.h>
 
-#ifdef __mips__
+#if defined(__mips__) && defined(__glibc__)
 /* Include definitions of the ABI currently in use.                          */
 #include <sgidefs.h>
 #endif