[xen staging] automation/alpine: add g++ to the list of build depends

[patchbot@xxxxxxx]

commit 5ee8e367f26082fb02b40319a019c795571f3f8e
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Mon Mar 1 10:57:14 2021 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Mon Mar 8 18:20:59 2021 -0800

    automation/alpine: add g++ to the list of build depends
    
    clang++ relies on the C++ headers installed by g++, or else a clang
    build will hit the following error:
    
    <built-in>:3:10: fatal error: 'cstring' file not found
    #include "cstring"
             ^~~~~~~~~
    1 error generated.
    make[10]: *** [Makefile:120: headers++.chk] Error 1
    
    Link: https://gitlab.alpinelinux.org/alpine/aports/-/issues/12492
    Reported-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Release-Acked-by: Ian Jackson <iwj@xxxxxxxxxxxxxx>
---
 automation/build/alpine/3.12.dockerfile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/automation/build/alpine/3.12.dockerfile 
b/automation/build/alpine/3.12.dockerfile
index 2c02417ee6..94557e239b 100644
--- a/automation/build/alpine/3.12.dockerfile
+++ b/automation/build/alpine/3.12.dockerfile
@@ -21,6 +21,7 @@ RUN \
   apk add curl-dev && \
   apk add dev86 && \
   apk add gcc  && \
+  apk add g++ && \
   apk add clang  && \
   apk add gettext && \
   apk add git && \
--
generated by git-patchbot for /home/xen/git/xen.git#staging