main/gcc: re-enable support for gcc-go

Disabled in c29fc976.

main/gcc/0042-stddef.h-add-support-for-musl-typedef-macro-guards.patch

+From b9e9895826774d17d4bb81b165753816db562590 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?S=C3=B6ren=20Tempel?= <soeren+git@soeren-tempel.net>
+Date: Thu, 25 Nov 2021 17:44:04 +0100
+Subject: [PATCH] stddef.h: add support for musl typedef macro guards
+
+The stddef.h header checks/sets various hardcoded toolchain/os specific
+macro guards to prevent redefining types such as ptrdiff_t, wchar_t, or
+size_t. However, without this patch, the file does not check/set the
+typedef macro guards for musl libc. This causes types such as size_t to
+be defined twice for files which include both musl's stddef.h as well as
+GCC's ginclude/stddef.h. This is, for example, the case for
+libgo/sysinfo.c. If libgo/sysinfo.c has multiple typedefs for size_t
+this confuses -fdump-go-spec and causes size_t not to be included in the
+generated type definitions thereby causing a gcc-go compilation failure
+on musl with the following error message:
+
+	sysinfo.go:7765:13: error: use of undefined type '_size_t'
+	 7765 | type Size_t _size_t
+	      |             ^
+	libcall_posix.go:49:35: error: non-integer len argument in make
+	   49 |                 b := make([]byte, len)
+	      |
+
+This commit fixes this issue by ensuring that ptrdiff_t, wchar_t, and size_t
+are only defined once in the pre-processed libgo/sysinfo.c file by enhancing
+gcc/ginclude/stddef.h with musl-specific typedef macro guards.
+---
+ gcc/ginclude/stddef.h | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+diff --git a/gcc/ginclude/stddef.h b/gcc/ginclude/stddef.h
+index 66619fe43b1..50d710a5ab9 100644
+--- a/gcc/ginclude/stddef.h
++++ b/gcc/ginclude/stddef.h
+@@ -128,6 +128,7 @@ _TYPE_wchar_t;
+ #ifndef ___int_ptrdiff_t_h
+ #ifndef _GCC_PTRDIFF_T
+ #ifndef _PTRDIFF_T_DECLARED /* DragonFly */
++#ifndef __DEFINED_ptrdiff_t /* musl libc */
+ #define _PTRDIFF_T
+ #define _T_PTRDIFF_
+ #define _T_PTRDIFF
+@@ -137,10 +138,12 @@ _TYPE_wchar_t;
+ #define ___int_ptrdiff_t_h
+ #define _GCC_PTRDIFF_T
+ #define _PTRDIFF_T_DECLARED
++#define __DEFINED_ptrdiff_t
+ #ifndef __PTRDIFF_TYPE__
+ #define __PTRDIFF_TYPE__ long int
+ #endif
+ typedef __PTRDIFF_TYPE__ ptrdiff_t;
++#endif /* __DEFINED_ptrdiff_t */
+ #endif /* _PTRDIFF_T_DECLARED */
+ #endif /* _GCC_PTRDIFF_T */
+ #endif /* ___int_ptrdiff_t_h */
+@@ -174,6 +177,7 @@ typedef __PTRDIFF_TYPE__ ptrdiff_t;
+ #ifndef _SIZE_T_DEFINED
+ #ifndef _BSD_SIZE_T_DEFINED_	/* Darwin */
+ #ifndef _SIZE_T_DECLARED	/* FreeBSD 5 */
++#ifndef __DEFINED_size_t	/* musl libc */
+ #ifndef ___int_size_t_h
+ #ifndef _GCC_SIZE_T
+ #ifndef _SIZET_
+@@ -191,6 +195,7 @@ typedef __PTRDIFF_TYPE__ ptrdiff_t;
+ #define _SIZE_T_DEFINED
+ #define _BSD_SIZE_T_DEFINED_	/* Darwin */
+ #define _SIZE_T_DECLARED	/* FreeBSD 5 */
++#define __DEFINED_size_t	/* musl libc */
+ #define ___int_size_t_h
+ #define _GCC_SIZE_T
+ #define _SIZET_
+@@ -215,6 +220,7 @@ typedef long ssize_t;
+ #endif /* _SIZET_ */
+ #endif /* _GCC_SIZE_T */
+ #endif /* ___int_size_t_h */
++#endif /* __DEFINED_size_t */
+ #endif /* _SIZE_T_DECLARED */
+ #endif /* _BSD_SIZE_T_DEFINED_ */
+ #endif /* _SIZE_T_DEFINED */
+@@ -251,6 +257,7 @@ typedef long ssize_t;
+ #ifndef _BSD_WCHAR_T_DEFINED_    /* Darwin */
+ #ifndef _BSD_RUNE_T_DEFINED_	/* Darwin */
+ #ifndef _WCHAR_T_DECLARED /* FreeBSD 5 */
++#ifndef __DEFINED_wchar_t /* musl libc */
+ #ifndef _WCHAR_T_DEFINED_
+ #ifndef _WCHAR_T_DEFINED
+ #ifndef _WCHAR_T_H
+@@ -272,6 +279,7 @@ typedef long ssize_t;
+ #define __INT_WCHAR_T_H
+ #define _GCC_WCHAR_T
+ #define _WCHAR_T_DECLARED
++#define __DEFINED_wchar_t
+ 
+ /* On BSD/386 1.1, at least, machine/ansi.h defines _BSD_WCHAR_T_
+    instead of _WCHAR_T_, and _BSD_RUNE_T_ (which, unlike the other
+@@ -326,6 +334,7 @@ typedef __WCHAR_TYPE__ wchar_t;
+ #endif
+ #endif
+ #endif
++#endif /* __DEFINED_wchar_t */
+ #endif /* _WCHAR_T_DECLARED */
+ #endif /* _BSD_RUNE_T_DEFINED_ */
+ #endif

main/gcc/APKBUILD

@@ -8,7 +8,7 @@ pkgver=11.2.1_git20211125
 [ "$CHOST" != "$CTARGET" ] && _target="-$CTARGET_ARCH" || _target=""
 
 pkgname="$pkgname$_target"
-pkgrel=0
+pkgrel=1
 pkgdesc="The GNU Compiler Collection"
 url="https://gcc.gnu.org"
 arch="all"
@@ -24,8 +24,7 @@ replaces="libstdc++ binutils"
 : "${LANG_CXX:=true}"
 : "${LANG_D:=true}"
 : "${LANG_OBJC:=true}"
-# Go frontend presently fails to build due to missing _size_t type in sysinfo.go.
-: "${LANG_GO:=false}"
+: "${LANG_GO:=true}"
 : "${LANG_FORTRAN:=true}"
 : "${LANG_ADA:=true}"
 
@@ -214,6 +213,7 @@ source="https://dev.alpinelinux.org/~nenolod/gcc-${pkgver}.tar.xz
 	0039-Use-generic-errstr.go-implementation-on-musl.patch
 	0040-configure-Add-enable-autolink-libatomic-use-in-LINK_.patch
 	0041-configure-fix-detection-of-atomic-builtins-in-libato.patch
+	0042-stddef.h-add-support-for-musl-typedef-macro-guards.patch
 	"
 
 # we build out-of-tree
@@ -704,4 +704,5 @@ f7eefa7ae1f31fc7bc1721578d4c1642f2ef5feda37dec03264dde53717474437722ee646ab9a837
 83deca7a68c6e1ce934f79b5d1e1a4b8b8a25c7bc24c3ef934307c232e168d9b17048a00a040fe81ac0cf6d4a23beefb292369c35d9896dab440dda228c90b0a  0039-Use-generic-errstr.go-implementation-on-musl.patch
 4074c62c2ee0ed555f01bf0cc69e32ef275bc3ac74de1d428ba1a2ac59fae973fe6f9aab8b3796df4bda7ab7cf220e5e1cbfdf103f41e4cbea175067a947d08f  0040-configure-Add-enable-autolink-libatomic-use-in-LINK_.patch
 1fe1b1e9ec288f65cd0d80a74b0a060b29c40e501f666b01e2825b61949be4568aeaf7cf473142889a7fd5e011b096837a651582d64fce67500fcb2ba39e16ce  0041-configure-fix-detection-of-atomic-builtins-in-libato.patch
+0a66c5a567e15dafac0bcad5c9dd5e98c44c74cbe539340ad28cbf6d26b994bab46b355f3a3a57b830f802145cfd826ad8d87359ebc5d6a20ef41e968904c7dc  0042-stddef.h-add-support-for-musl-typedef-macro-guards.patch
 "