runtime: convert symtab.c into symtab.go
Because symtab.c was partially converted before,
the diffs are not terribly useful.
The earlier conversion was trying to refactor or
clean up the code in addition to doing the translation.
It also made a mistake by redefining Func to be something
users could overwrite.
I undid those changes, making symtab.go a more
literal line-for-line translation of symtab.c instead.
LGTM=josharian
R=golang-codereviews, dave, bradfitz, josharian
CC=golang-codereviews, iant, khr, r
https://golang.org/cl/140880043
diff --git a/src/pkg/runtime/funcdata.h b/src/pkg/runtime/funcdata.h
index 85e8283..dc9c413 100644
--- a/src/pkg/runtime/funcdata.h
+++ b/src/pkg/runtime/funcdata.h
@@ -6,6 +6,8 @@
// in Go binaries. It is included by both C and assembly, so it must
// be written using #defines. It is included by the runtime package
// as well as the compilers.
+//
+// symtab.go also contains a copy of these constants.
#define PCDATA_ArgSize 0 /* argument size at CALL instruction */
#define PCDATA_StackMapIndex 1
