package/qt5/qt5webengine: don't link with libstdc++.a on the host

While cross-compiling, qt5webengine is building a host tool, 'gn', and
by default wants to link it statically with libstdc++, when the tool is
otherwise dynamically linked with other libraries:

    $ ldd 3rdparty/gn/out/Release/gn
        linux-vdso.so.1 (0x00007ffc1c999000)
        libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f48a3c06000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f48a3be4000)
        libc.so.6 => /lib64/libc.so.6 (0x00007f48a3a1b000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f48a3c53000)

Not all ditributions have the static libraries installed by default; for
example, on Fedora, libstdc++-static is not installed on a fresh system,
leading to build issues:

  [185/185] LINK gn
  FAILED: gn
  /usr/bin/g++ -O3 -fdata-sections -ffunction-sections -Wl,--gc-sections -Wl,-strip-all -Wl,--as-needed -static-libstdc++ -pthread -o gn -Wl,--start-group tools/gn/gn_main.o base.a gn_lib.a -Wl,--end-group -ldl
  /usr/bin/ld : unable to find -lstdc++
  [...]
  Project ERROR: GN build error!

The root cause is the addition in [0] of a command line option to the
build of gn, that requests static linking with libstdc++ by default.

Explicitly pass that option now, to avoid static linking with libstdc++
and get a fully dynamicallty linked executable:

    $ ldd 3rdparty/gn/out/Release/gn
        linux-vdso.so.1 (0x00007ffd3f160000)
        libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f68138e7000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f68138c5000)
        libc.so.6 => /lib64/libc.so.6 (0x00007f68136fc000)
        libm.so.6 => /lib64/libm.so.6 (0x00007f68135b6000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f6813b13000)
        libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f681359c000)

[0] cfab9198a9 (diff-905c8f054808213577c0a92d1b704615)

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Gaël Portay <gael.portay@collabora.com>
[yann.morin.1998@free.fr:
  - rewrite the commit log with extra details and explanations
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
This commit is contained in:
Romain Naour 2020-05-24 17:58:18 +02:00 committed by Yann E. MORIN
parent 58ecbbc3ef
commit f9548114d8

View File

@ -0,0 +1,51 @@
From 7ae73da23ad998bd1e63ad213cf7a02e61191951 Mon Sep 17 00:00:00 2001
From: Romain Naour <romain.naour@gmail.com>
Date: Sat, 23 May 2020 19:01:19 +0200
Subject: [PATCH] gn.pro: don't link statically with libstc++
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
While cross-compiling, qt5webengine is building a host tool but
want to link the libstdc++ statically. This requires to install
libstdc++-static package on the host (Fedora package name).
Otherwise the link fail with:
[185/185] LINK gn
FAILED: gn
/usr/bin/g++ -O3 -fdata-sections -ffunction-sections -Wl,--gc-sections -Wl,-strip-all -Wl,--as-needed -static-libstdc++ -pthread -o gn -Wl,--start-group tools/gn/gn_main.o base.a gn_lib.a -Wl,--end-group -ldl
/usr/bin/ld : unable to find -lstdc++
[...]
Project ERROR: GN build error!
Add --no-static-libstdc++ argument to gn.pro to link to
libstdc++.so.6 instead of libstdc++.a.
--no-static-libstdc++ has been added by [1] but it force
linking statically by default.
[1] https://github.com/qt/qtwebengine-chromium/commit/cfab9198a9917f42cf08b1caf84ab9b71aac1911#diff-905c8f054808213577c0a92d1b704615
Signed-off-by: Romain Naour <romain.naour@gmail.com>
---
src/buildtools/gn.pro | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/buildtools/gn.pro b/src/buildtools/gn.pro
index 033202e6..5dd8e241 100644
--- a/src/buildtools/gn.pro
+++ b/src/buildtools/gn.pro
@@ -20,7 +20,8 @@ build_pass|!debug_and_release {
gn_gen_args = --no-last-commit-position --out-path $$out_path \
--cc \"$$which($$QMAKE_CC)\" --cxx \"$$which($$QMAKE_CXX)\" \
- --ld \"$$which($$QMAKE_LINK)\"
+ --ld \"$$which($$QMAKE_LINK)\" \
+ --no-static-libstdc++
msvc:!clang_cl: gn_gen_args += --use-lto
--
2.25.4