Strange thing is that when building gcc-4.2.x on NetBSD/amd64 machine,

 361  12:35   ../gcc-4.2.4/configure --enable-languages=c --host=amd64--netbsd

I am getting following problem.

/export/local-src/gcc-4.2.4-work-amd64-enable-c-fail/./prev-gcc/xgcc
-B/export/local-src/gcc-4.2.4-work-amd64-enable-c-fail/./prev-gcc/
-B/usr/local/amd64--netbsd/bin/ -c -DHAVE_CONFIG_H -g -O2
-I. -I../../gcc-4.2.4/libiberty/../include -W -Wall -pedantic
-Wwrite-strings -Wstrict-prototypes -Wc++-compat
../../gcc-4.2.4/libiberty/mempcpy.c -o mempcpy.o
../../gcc-4.2.4/libiberty/mempcpy.c:35: 
	error: expected declaration specifiers or '...' before 'size_t'
../../gcc-4.2.4/libiberty/mempcpy.c:35: 
	warning: conflicting types for built-in function 'memcpy'
../../gcc-4.2.4/libiberty/mempcpy.c:38: 
	error: expected declaration specifiers or '...' before 'size_t'
../../gcc-4.2.4/libiberty/mempcpy.c:39: 
	warning: conflicting types for built-in function 'mempcpy'
../../gcc-4.2.4/libiberty/mempcpy.c: In function 'mempcpy':
../../gcc-4.2.4/libiberty/mempcpy.c:40: error: 'len' undeclared (first use in this function)
../../gcc-4.2.4/libiberty/mempcpy.c:40: 
	error: (Each undeclared identifier is reported only once
../../gcc-4.2.4/libiberty/mempcpy.c:40: error: for each function it appears in.)
../../gcc-4.2.4/libiberty/mempcpy.c:40: error: too many arguments to function 'memcpy'

gmake[3]: *** [mempcpy.o] Error 1
gmake[3]: Leaving directory `/export/local-src/gcc-4.2.4-work-amd64-enable-c-fail/libiberty'

But by applying following patch, at least configuration shown above build completes.

--- gcc-4.2.4/include/ansidecl.h-orig	2005-07-04 00:38:39.000000000 +0900
+++ gcc-4.2.4/include/ansidecl.h	2009-01-19 14:23:58.000000000 +0900
@@ -368,4 +368,7 @@
 #define __extension__
 #endif
 
+#if defined(__x86_64__)
+typedef unsigned long size_t;
+#endif
 #endif	/* ansidecl.h	*/