runtime: rename Sigaltstack to SigaltstackT
Avoids a conflict between the type and function sigaltstack.
LGTM=crawshaw
R=rsc, crawshaw
CC=golang-codereviews
https://golang.org/cl/138920043
diff --git a/src/pkg/runtime/defs1_linux.go b/src/pkg/runtime/defs1_linux.go
index 451817a..392cc4a 100644
--- a/src/pkg/runtime/defs1_linux.go
+++ b/src/pkg/runtime/defs1_linux.go
@@ -31,7 +31,7 @@
type Xmmreg1 C.struct__xmmreg
type Fpstate1 C.struct__fpstate
type Fpreg1 C.struct__fpreg
-type Sigaltstack C.struct_sigaltstack
+type SigaltstackT C.struct_sigaltstack
type Mcontext C.mcontext_t
type Ucontext C.ucontext_t
type Sigcontext C.struct_sigcontext