configure / meson: Move check for sys/kcov.h to meson.build

This check can be done in a much shorter way in meson.build. And while
we're at it, rename the #define to HAVE_SYS_KCOV_H to match the other
HAVE_someheader_H symbols that we already have.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201118171052.308191-6-thuth@redhat.com>
[lv: s/signal/kcov/]
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

configure

@@ -4402,12 +4402,6 @@ if compile_prog "" "" ; then
   syncfs=yes
 fi
 
-# check for kcov support (kernel must be 4.4+, compiled with certain options)
-kcov=no
-if check_include sys/kcov.h ; then
-    kcov=yes
-fi
-
 # check for btrfs filesystem support (kernel must be 3.9+)
 btrfs=no
 if check_include linux/btrfs.h ; then
@@ -6112,9 +6106,6 @@ fi
 if test "$syncfs" = "yes" ; then
   echo "CONFIG_SYNCFS=y" >> $config_host_mak
 fi
-if test "$kcov" = "yes" ; then
-  echo "CONFIG_KCOV=y" >> $config_host_mak
-fi
 if test "$btrfs" = "yes" ; then
   echo "CONFIG_BTRFS=y" >> $config_host_mak
 fi