Native cross compilation

[crazy-max]

Fyi @tonistiigi

~1min against ~10min with qemu

[crazy-max]

Ah I guess the build time is great because external libs for additional features (gnutls, libsecret, ) are not found:

#54 165.1 Install prefix ......... : /usr
#54 165.1 NLS support ............ : yes
#54 165.1 TLS support ............ : yes (Library: GnuTLS)
#54 165.1 IDN support ............ : yes (via GNU Libidn)
#54 165.1 GNU SASL support ....... : no (most likely unnecessary)
#54 165.1 Libsecret support (GNOME): yes
#54 165.1 MacOS X Keychain support : no
#54 165.1 Build msmtpd ............: yes
#54 166.8 /usr/bin/make  all-recursive

previously https://github.com/crazy-max/docker-msmtpd/runs/3627172553?check_suite_focus=true#step:8:2948

#42 11.92 Install prefix ......... : /usr
#42 11.92 NLS support ............ : yes
#42 11.92 TLS support ............ : no (Library: none)
#42 11.92 IDN support ............ : no
#42 11.92 GNU SASL support ....... : no (most likely unnecessary)
#42 11.92 Libsecret support (GNOME): no
#42 11.92 MacOS X Keychain support : no
#42 11.93 Build msmtpd ............: yes

xx: https://github.com/crazy-max/docker-msmtpd/runs/3627353227?check_suite_focus=true#step:8:1244

EDIT: Yeah I need xx-apk for each of them.

[crazy-max]

Ok now I have a linker issue:

...
/usr/bin/armv7-alpine-linux-musleabihf-ld: warning: libp11-kit.so.0, needed by /armv7-alpine-linux-musleabihf/usr/lib/libgnutls.so, not found (try using -rpath or -rpath-link)

https://github.com/crazy-max/docker-msmtpd/pull/34/checks?check_run_id=3627893666#step:8:2608

[tonistiigi]

The easiest fix (for non-s390x) is to just use lld instead:

diff --git a/Dockerfile b/Dockerfile
index f249934..603e529 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,7 +5,7 @@ ARG XX_VERSION=1.0.0-rc.2
 FROM --platform=$BUILDPLATFORM tonistiigi/xx:${XX_VERSION} AS xx
 FROM --platform=$BUILDPLATFORM crazymax/alpine-s6:${ALPINE_S6_VERSION} AS builder
 RUN apk --update --no-cache add \
-    clang \
+    clang lld \
     curl \
     file \
     make \
@@ -20,7 +20,7 @@ WORKDIR /src
 RUN curl -sSL "https://marlam.de/msmtp/releases/msmtp-$MSMTP_VERSION.tar.xz" | tar xJv --strip 1
 
 ARG TARGETPLATFORM
-ENV XX_CC_PREFER_LINKER=ld
+# ENV XX_CC_PREFER_LINKER=ld
 COPY --from=xx / /
 RUN xx-apk --no-cache add \
     g++ \

If ld is preferred then following fixes

diff --git a/Dockerfile b/Dockerfile
index f249934..b10d3da 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -31,6 +31,7 @@ RUN xx-apk --no-cache add \
     libgsasl-dev \
     libsecret-dev
 RUN set -x \
+  && export LDFLAGS="-Wl,-rpath-link,/$(xx-info)/usr/lib" \
   && ./configure \
     --host=$(xx-clang --print-target-triple) \
     --prefix=/usr \

We can set this automatically in xx in the cfg file but I'd like to understand more what the actual difference and what would be the cleanest fix.

Don't forget to use xx-verify as well.