Some more build fixes from OpenSUSE

These update some outdated library path searches as well as
a couple of gcc-specific improvements.

Original patch:
https://build.opensuse.org/package/view_file/shells/ksh/ksh93-compat.dif

src/lib/libast/astsa/ast.h

@@ -93,6 +93,12 @@ typedef struct
 #define pointerof(x)	((void*)((char*)0+(x)))
 #define roundof(x,y)	(((x)+(y)-1)&~((y)-1))
 
+#ifdef __GNUC__
+#if (__GNUC__ >= 4) && !defined(offsetof)
+#define offsetof(type,member)	__builtin_offsetof(type,member)
+#endif
+#endif
+
 #ifndef offsetof
 #define offsetof(type,member) ((unsigned long)&(((type*)0)->member))
 #endif

src/lib/libast/features/libpath.sh

@@ -27,7 +27,7 @@ esac
 
 ok=0
 for i in \
-	-x /lib/ld.so /lib/ld-*.so /usr/lib/ld.so /lib/rld \
+	-x /lib64/ld.so /lib/ld.so /lib64/ld-*.so /lib/ld-*.so /usr/lib/ld.so /lib/rld \
 	-f /usr/shlib/libc.so /shlib/libc.so /usr/lib/libc.so \
 	-r /usr/shlib/libc.so /shlib/libc.so
 do	case $i in

src/lib/libast/features/map.c

@@ -67,10 +67,14 @@ main()
 #define _map_malloc	1
 	printf("\n");
 	printf("#define	_map_libc	1\n");
+#endif
+#if _map_libc || defined(__linux__)
 	printf("#undef	basename\n");
 	printf("#define basename	_ast_basename\n");
 	printf("#undef	dirname\n");
 	printf("#define dirname		_ast_dirname\n");
+#endif
+#if _map_libc
 #if !_lib_eaccess
 	printf("#undef	eaccess\n");
 	printf("#define eaccess		_ast_eaccess\n");

src/lib/libast/features/sys

@@ -134,7 +134,7 @@ tst	typ_signed_size_t output{
 	}
 }end
 
-define	offsetof	(type,member)	((size_t)&(((type*)0)->member))
+define	offsetof	(type,member)	__builtin_offsetof(type,member)
 define	EXIT_FAILURE	1
 define	EXIT_SUCCESS	0
 define	MB_CUR_MAX	1

src/lib/libdll/features/dll

@@ -15,7 +15,7 @@ tst	dll_DYNAMIC link{
 }end
 tst	run{
 	lib=
-	for d in  /shlib /usr/shlib /lib /usr/lib
+	for d in  /lib64 /usr/lib64 /lib /usr/lib
 	do	if	test -d $d
 		then	for s in "*.*" "*[!a]*"
 			do	for b in libc
@@ -52,7 +52,7 @@ tst	run{
 	"")	lib=/lib/libc.so.1 ;;
 	esac
 	case $lib in
-	/usr/lib/*)
+	/usr/lib64/*|/usr/lib/*)
 		case `package` in
 		sgi.mips3)
 			abi=/lib32
@@ -65,7 +65,7 @@ tst	run{
 		esac
 		case $abi in
 		?*)	if	test -d $abi
-			then	lib=`echo $lib | sed 's,/usr/lib/,,'`
+			then	lib=`echo $lib | sed 's,/usr/lib\(64\)\?/,,'`
 				lib=$abi/$lib
 			fi
 			;;