build: clear execute bit from source files

R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/5201042

diff --git a/src/pkg/math/atan2_386.s b/src/pkg/math/atan2_386.s
old mode 100755 (executable)
new mode 100644 (file)

diff --git a/src/pkg/runtime/cgo/386.S b/src/pkg/runtime/cgo/386.S
old mode 100755 (executable)
new mode 100644 (file)

diff --git a/src/pkg/runtime/cgo/windows_386.c b/src/pkg/runtime/cgo/windows_386.c
old mode 100755 (executable)
new mode 100644 (file)

diff --git a/src/pkg/runtime/cgo/windows_amd64.c b/src/pkg/runtime/cgo/windows_amd64.c
old mode 100755 (executable)
new mode 100644 (file)