bump datasize of the build user to 2.5G on 64-bit arches

The tight limit of 2176M for other 64-bit architectures was not enough for
sparc64. On 64-bit systems we can afford to be a bit more generous.
login.conf merges are always a bit fiddly.

ok jca sthen

etc/etc.amd64/login.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: login.conf,v 1.28 2026/05/15 15:31:32 robert Exp $
+# $OpenBSD: login.conf,v 1.29 2026/05/24 15:47:39 tb Exp $
 
 #
 # Sample login.conf file.  See login.conf(5) for details.
@@ -90,8 +90,8 @@ authpf:\
 # Building LLVM in base requires higher limits
 #
 build:\
-	:datasize-max=2176M:\
-	:datasize-cur=2176M:\
+	:datasize-max=2560M:\
+	:datasize-cur=2560M:\
 	:tc=default:
 
 #

etc/etc.arm64/login.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: login.conf,v 1.20 2026/05/15 15:31:32 robert Exp $
+# $OpenBSD: login.conf,v 1.21 2026/05/24 15:47:39 tb Exp $
 
 #
 # Sample login.conf file.  See login.conf(5) for details.
@@ -91,8 +91,8 @@ authpf:\
 # Building LLVM in base requires higher limits
 #
 build:\
-	:datasize-max=2176M:\
-	:datasize-cur=2176M:\
+	:datasize-max=2560M:\
+	:datasize-cur=2560M:\
 	:tc=default:
 
 #

etc/etc.powerpc64/login.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: login.conf,v 1.11 2026/05/15 15:31:32 robert Exp $
+# $OpenBSD: login.conf,v 1.12 2026/05/24 15:47:39 tb Exp $
 
 #
 # Sample login.conf file.  See login.conf(5) for details.
@@ -90,8 +90,8 @@ authpf:\
 # Building LLVM in base requires higher limits
 #
 build:\
-	:datasize-max=2176M:\
-	:datasize-cur=2176M:\
+	:datasize-max=2560M:\
+	:datasize-cur=2560M:\
 	:tc=default:
 
 #

etc/etc.sparc64/login.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: login.conf,v 1.25 2025/07/17 14:44:42 landry Exp $
+# $OpenBSD: login.conf,v 1.26 2026/05/24 15:47:39 tb Exp $
 
 #
 # Sample login.conf file.  See login.conf(5) for details.
@@ -90,8 +90,8 @@ authpf:\
 # Building LLVM in base requires higher limits
 #
 build:\
-	:datasize-max=2000M:\
-	:datasize-cur=2000M:\
+	:datasize-max=2560M:\
+	:datasize-cur=2560M:\
 	:tc=default:
 
 #