buildroot

Fix build with gcc 4.9

​

cairo fails to build with gcc 4.9 due to a bad interaction of cairo

modules with the LTO mechanism. The suggested workaround is to pass

-ffat-lto-objects. See

https://bugs.freedesktop.org/show_bug.cgi?id=77060 for the upstream

bug report, and

https://bugs.archlinux.org/task/40313?project=1&openedfrom=-1+week for

the ArchLinux bug report.

​

This patch passes -ffat-lto-objects when gcc understands this option,

in order to provide compatibility with gcc versions older than 4.8,

which did not provide this option, but are anyway unaffected by the

issue.

​

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

​

Index: b/configure.ac

===================================================================

--- a/configure.ac

+++ b/configure.ac

@@ -37,6 +37,16 @@

 m4_include(build/configure.ac.pthread)  dnl checks for pthreads

 AC_CACHE_SAVE

+old_cflags=$CFLAGS

+CFLAGS=-ffat-lto-objects

+AC_MSG_CHECKING([whether CC supports -ffat-lto-objects])

+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])],

+    [AC_MSG_RESULT([yes])]

+    [LTO_CFLAGS=-ffat-lto-objects],

+    [AC_MSG_RESULT([no])]

+)

+CFLAGS="${old_CFLAGS} ${LTO_CFLAGS}"

+

 dnl ===========================================================================

 AC_CHECK_LIB(z, compress,