CMake: disable -Wmissing-field-initializers for broken compilers

AppleClang 9.1.0.9020039 is complaining about a "missing initializer" in
dumpcap.c. Rather than doing ugly things like one of the following:

    struct s x;
    memset(&x, 0, sizeof(x));
    struct s y = {.field=0};

just disable the warning (enabled via -Wextra) on broken compilers. The
minimum versions were determined using https://gcc.godbolt.org/

The special "universal zero initializer { 0 }" exception is explicitly
documented in the GCC manual (as shipped with GCC 8.2.1). Clang 6 does
not document it, but r314499 (as included with Clang 6) does implement
it and adds tests for it. (Xcode 10.0 seems based on Clang 6.0.1.)

Change-Id: I8e48d8c424a512ca36ef8c4f832ce81b3675232c
Reviewed-on: https://code.wireshark.org/review/30684
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

0 files changed, 0 insertions, 0 deletions