I have been experiencing problems compiling proftpd as position independent 
code on my older glibc (RH 7.3). The problem is that with older glibcs' 
_syscallN() it is neccessary tu push/pop %ebx register around the syscall
(%ebx is used as output, which is not acceptable in position independent
code). As far as I know, however, newer glibcs do not suffer from this problem.

							--- JiKos

--- cap_sys.c.old	2004-11-19 14:55:50 +0100
+++ cap_sys.c	2004-11-19 14:50:55 +0100
@@ -11,11 +11,20 @@
 #define __LIBRARY__
 #include <linux/unistd.h>
 
-_syscall2(int, capget,
+#define _syscall2_pic(type,name,type1,arg1,type2,arg2) \
+type name(type1 arg1,type2 arg2) \
+{ \
+long __res; \
+__asm__ volatile ("pushl %%ebx; movl %2,%%ebx; int $0x80; popl %%ebx" \
+        : "=a" (__res) \
+        : "0" (__NR_##name),"g" ((long)(arg1)),"c" ((long)(arg2))); \
+__syscall_return(type,__res); \
+}
+_syscall2_pic(int, capget,
 	  cap_user_header_t, header,
 	  cap_user_data_t, data)
 
-_syscall2(int, capset,
+_syscall2_pic(int, capset,
 	  cap_user_header_t, header,
 	  const cap_user_data_t, data)