cmd/ld: steps toward 386 host linking

- Introduce MaxAlign constant and use in data layout
and ELF section header.

- Allow up to 16-byte alignment for large objects
(will help Keith's hash changes).

- Emit ELF symbol for .rathole (global /dev/null used by 8c).

- Invoke gcc with -m32/-m64 as appropriate.

- Don't invoke gcc if writing the .o file failed.

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7563045

1 files changed, 1 insertions, 0 deletions

diff --git a/src/cmd/5l/l.h b/src/cmd/5l/l.h
index 059e269a91..0b31b07ab6 100644
--- a/src/cmd/5l/l.h
+++ b/src/cmd/5l/l.h
@@ -38,6 +38,7 @@ enum
 	thechar = '5',
 	PtrSize = 4,
 	IntSize = 4,
+	MaxAlign = 8,	// max data alignment
 	FuncAlign = 4  // single-instruction alignment
 };