fix(check_symbol_exists): Make it ISO C99 compliant.

This bug was reported in https://cmake.org/Bug/view.php?id=13208

We could try to bring C89 compat (is it worthwile ?) if we try sizeof on some
type like int/long/long long/... but this would be fragile.
23 jobs for !5660 with enhance_check_symbol_exists in 145 minutes and 23 seconds (queued for 1 second)
latest detached
Status Job ID Name Coverage
  Build
passed #5440991
linux docker cmake build manual
build:centos6-release

00:06:54

passed #5440988
linux docker cmake build
build:debian10-iwyu

00:02:34

passed #5440992
linux docker cmake build linux-3.17 manual
build:fedora33-ninja

00:01:11

passed #5440990
linux docker cmake build linux-3.17
build:fedora33-sphinx

00:04:16

passed #5440989
linux docker cmake build linux-3.17
build:fedora33-tidy

00:04:30

passed #5440994
cmake macos shell nonconcurrent xcode-12.2 manual
build:macos-makefiles

00:02:06

passed #5440993
cmake macos shell nonconcurrent xcode-12.2 manual
build:macos-ninja

00:09:08

passed #5440995
windows cmake shell vs2019 nonconcurrent msvc-19.28 manual
build:windows-vs2019-x64-ninja

00:05:32

 
  Test
passed #5440996
linux docker cmake x11 linux-3.17
test:fedora33-ninja

00:04:14

passed #5440998
cmake macos shell nonconcurrent xcode-12.2
test:macos-makefiles

00:08:52

passed #5440997
cmake macos shell nonconcurrent xcode-12.2
test:macos-ninja

00:11:58

passed #5441103
windows cmake shell vs2019 nonconcurrent msvc-19.28
test:windows-vs2019-x64-ninja

00:26:23

failed #5440999
windows cmake shell vs2019 nonconcurrent msvc-19.28
test:windows-vs2019-x64-ninja

00:17:51

 
  Test Ext
passed #5441002
linux docker cmake cuda-rt
test:cuda10.2-nvidia

00:02:46

passed #5441000
linux docker cmake build linux-3.17
test:debian10-ninja

00:02:28

passed #5441001
linux docker cmake build linux-3.17
test:fedora33-makefiles

00:02:45

passed #5441003
linux docker cmake build linux-3.17
test:fedora33-ninja-multi

00:03:31

failed #5441004
cmake macos shell concurrent xcode-12.2
test:macos-xcode

00:55:26

passed #5441005
windows cmake shell vs2019 concurrent msvc-19.28
test:windows-vs2019-x64

00:37:45

 
  External
passed cdash

passed ghostflow-check-master

passed cdash

passed cdash

 
Name Stage Failure
failed
test:macos-xcode Test Ext
   Send to group: merge-requests
SubmitURL: http://open.cdash.org/submit.php?project=CMake
Uploaded: /opt/glr/cmake/cmake ci ext/1/build/Testing/20210102-0541/Test.xml
Submission successful
CMake Error at /opt/glr/cmake/cmake ci ext/1/.gitlab/ci/ctest_test_external.cmake:77 (message):
Failed to test


ERROR: Job failed: exit status 1