configure: bump min required GCC to 7.4.0

Several distros have been dropped since the last time we bumped the
minimum required GCC version.

Per repology, currently shipping versions are:

                 RHEL-8: 8.3.1
          Debian Buster: 8.3.0
     openSUSE Leap 15.2: 7.5.0
       Ubuntu LTS 18.04: 7.5.0
       Ubuntu LTS 20.04: 9.3.0
                FreeBSD: 10.3.0
              Fedora 33: 9.2.0
              Fedora 34: 11.0.1
                OpenBSD: 8.4.0
         macOS HomeBrew: 11.1.0

With this list Ubuntu LTS 18.04 / openSUSE Leap 15.2 are the
constraint at 7.5.0.

When QEMU bumped GCC to 7.5.0, however, it was reported that
this is a problem for NetBSD which still ships 7.4.0.

NetBSD is not an officially targetted platform for libvirt.
Given that QEMU saw complaints about this and the feature
difference between GCC 7.4.0 and 7.5.0 is minor, I'm being
friendly and sticking 7.4.0.

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/config.h b/config.h
index 0eacfd139d1c648cc65fd0a22858bc664efd77d6..2ef32c8627469ddaaf42400e03c4fab1a3508f75 100644 (file)
--- a/config.h
+++ b/config.h
@@ -45,9 +45,9 @@
 #  endif
 # endif
 #elif defined(__GNUC__) && defined(__GNUC_MINOR__)
-# if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 8)
-#  error You need at least GCC v4.8 to compile libvirt
+# if __GNUC__ < 7 || (__GNUC__ == 7 && __GNUC_MINOR__ < 4)
+#  error You need at least GCC v7.4.0 to compile libvirt
 # endif
 #else
-# error You either need at least GCC 4.8 or Clang 3.4 or XCode Clang 5.1 to compile libvirt
+# error You either need at least GCC 7.4.0 or Clang 3.4 or XCode Clang 5.1 to compile libvirt
 #endif